Firefox Extensions

Last updated April 2, 2020, 5:32 p.m. by Author

Tags: internet security software productivity firefox privacy

Below you can find an extensive and regularly updated list of Firefox extensions that are either essential or very useful when browsing the web. I have divided them in a few groups, to allow better navigation and selection according to your needs.

One advice for people eager to try new extensions - always check the extension's privacy policy. If it is longer that something like "We do not collect any user data.", be cautious. As a rule of thumb, try not to use any add-on that has a "Custom License" - install only the open source ones (Mozilla Public License, GNU GPL or MIT).

Because the list is periodically updated, if you want to stay up to date with the latest additions and deletions, you can use the Web Pages Scanner extension to be notified about any changes made here.

Security & Privacy

uBlock Origin

The top extensions, which is required when using a browser. This is simply the best adblocker out there. Required not only to get rid of those annoying ads but also to protect yourself from malicious elements that may appear on a website.

Additionaly you the basic block lists available in the uBlock's settings (not all of them are enabled by default), toy should consider subscribing to some additional filterlists which can be found here: FilterLists

Nano Defender for Firefox

An anti-adblock defuser for Nano Adblocker and uBlock Origin on Firefox.

It is designed for Nano Adblocker and uBlock Origin and does not work with other adblockers.

This extension allows you to circumvent the "disable AdBlock to view this website" popups.

There are a few extra installation steps when using together with uBlock Origin.

Cookie AutoDelete

The name says everything. Auto deletes your cookies according to specified rules. You can of course whitelist selected domains. This extension supports Firefox Containers.

Cookie Quick Manager

Cookie Quick Manager: A complete manager for cookies accumulated during browsing.

It allows you to view, edit, create, delete, backup, restore cookies and search them by domain names. Contextual Identities such as Private Browsing, First-Party Isolation, and SameSite flag are also supported.

In addition, the LocalStorage of the page viewed can be deleted (see below).

This WebExtension is compatible with Firefox 57 and is inspired by addons like Cookies Manager+ and Advanced Cookie Manager whose development has been discontinued due to the withdrawal of the support for "Legacy" extensions.

Features:

User friendly: Clear and structured user interface. Each parameter and functionality is described when the mouse is over the element.
Windowed and tab mode: Choose the opening in a tab to get a wider view.
Transparency and security: The source code is free (under GPLv3) and published on a public platform, the only way to allow reviews and external contributions.
Search: A user can search for cookies of a domain and subdomains which depend on it.
Edit/Create: All the attributes of a cookie can be modified: domain, path, name, value, expiration date, as well as secure and httponly flags.
Delete: Remove the cookies of the current website in two clicks.
Export: The export and import of one or many cookies from one or many domains at a time in JSON or Netscape format is just as easy.
First-Party Isolation: Supported with some limitations (due to API bugs) on Firefox 59, 60, and 61, and without limitations on Firefox 62 (scheduled on September 2018).
Contexts: Contexts (also called Multi-Account Containers, or Contextual Identities) are supported. A user can search and display cookies inside a container, or copy cookies from a container to another, or save a cookie in a specific context.
SameSite: The SameSite flag is supported. This is a partial protection against the risks associated with Cross-Site Request Forgery (CSRF) and Cross-Site Script Inclusion (XSSI) attacks, implemented since Firefox 63.
Cookie protection: Delete cookies except protected ones, with two clicks at anytime from the website you are viewing. An option can also prevent cookies from being deleted by the sites themselves.
Protection of session cookies: Session cookies can be protected in two clicks to prevent accidental logout from websites after cleaning normal cookies.
Cleaning and privacy: Can automatically delete all cookies at startup.
LocalStorage: Keys/values of the page viewed can be deleted.

Greasemonkey

Greasemonkey is a script manager. There are two other script managers: Tampermonkey and Violentmonkey, but the first one should be avoided. It is proprietary and collects user data. The second one used to have a shady privacy policy, which has been changed, so it now it can be a viable alternative to Greasemonkey.

Below you can find some useful scripts:
- AdsBypasser
- AntiAdware
- Mouseover Popup Image Viewer
- YouTube Unblocker
- Hide Ads on Facebook
- LinkedIn unsponsored
- Bypass paywalls for scientific documents
- MoreCAPTCHA
- Direct download from Google Play
- Local SoundCloud Downloader
- Local YouTube Downloader
- FuckFuckAdBlock

FuckFuckAdblock should not be used when NanoDefender is installed.

Additional scripts can be found on Greasy Fork.

Another promising script manager that is worth taking a look is FireMonkey

Decentraleyes

Protects you against tracking through "free", centralized, content delivery. It prevents a lot of requests from reaching networks like Google Hosted Libraries, and serves local files to keep sites from breaking. Complements regular content blockers.

After installing, check if Decentraleyes is operational. If not, follow the instructions provided.

HTTPS Everywhere

HTTPS Everywhere is a Firefox extension to protect your communications by enabling HTTPS encryption automatically on sites that are known to support it, even when you type URLs or follow links that omit the https: prefix.

TrackMeNot

An artware browser add-on to protect privacy in web-search. By issuing randomized queries to common search-engines, TrackMeNot obfuscates your search profile and registers your discontent with surreptitious tracking

KeePassXC-Browser

Official browser plugin for the KeePassXC password manager (https://keepassxc.org).

I used to recommend KeePass Tusk, which in my opinion is a bit more user friendly, but unfortunately it is no longer maintained.

Chameleon

Spoof your browser profile. Includes a few privacy enhancing options. The wiki explains all of the options available.

Multi Account Containers

Firefox Multi-Account Containers lets you keep parts of your online life separated into color-coded tabs that preserve your privacy. Cookies are separated by container, allowing you to use the web with multiple identities or accounts simultaneously. Here's a simple guide to using them.

Temporary Containers

Open tabs, websites, and links in automatically managed disposable containers. Containers isolate data websites store (cookies, storage, and more) from each other, enhancing your privacy and security while you browse.

uMatrix

Point & click to forbid/allow any class of requests made by your browser. Use it to block scripts, iframes, ads, facebook, etc.

This an extension for advanced users. There's a wiki/guide available on the developer's GitHub page. Because it is a bit complicated I will not get into details on how to use it.

NoScript

It allows JavaScript, Flash, Java and other executable content to run only from trusted domains of your choice, e.g. your home-banking site, mitigating remotely exploitable vulnerabilities including Spectre and Meltdown.

It protects your "trust boundaries" against cross-site scripting attacks (XSS), cross-zone DNS rebinding / CSRF attacks (router hacking), and Clickjacking attempts, thanks to its unique ClearClick technology.

Personally, I use only the XSS protection (Sanitize cross-site suspicious requests option checked) with all the restrictions disabled globally, because everything else is controlled by uMatrix which I find much better.

CSS Exfil Protection

CSS Exfil is a method attackers can use to steal data from web pages using Cascading Style Sheets (CSS). This plugin sanitizes and blocks any CSS rules which may be designed to steal data.

uBO Scope

A tool to measure your 3rd-party exposure score for web sites you visit. Here's a detailed description of its purpose.

Privacy Possum

Privacy Possum monkey wrenches common commercial tracking methods by reducing and falsifying the data gathered by tracking companies:

Blocks cookies that let trackers uniquely identify you across websites
Blocks refer headers that reveal your browsing location
Blocks etag tracking which leverages browser caching to uniquely identify you
List itemBlocks browser fingerprinting which tracks the inherent uniqueness of your browser

See here to read Privacy Possum's developer's comment on why you should use it together with uBlock Origin and Privacy Badger/uMatrix.

Privacy Badger

Privacy Badger automatically learns to block invisible trackers. Instead of keeping lists of what to block, Privacy Badger learns by watching which domains appear to be tracking you as you browse the Web.

Privacy Badger sends the Do Not Track signal with your browsing. If trackers ignore your wishes, your Badger will learn to block them. Privacy Badger starts blocking once it sees the same tracker on three different websites.

Besides automatic tracker blocking, Privacy Badger removes outgoing link click tracking on Facebook, Google and Twitter, with more privacy protections on the way.

Personally, I do not use this extension because Privacy Possum in conjunction with uMatrix are much more powerful, but Privacy Badger is suitable for beginners who do not want their websites to break often.

Location Guard

Hide your geographic location from websites. Report a fake location with the addition of random noise in order to protect your privacy. Per site settings with three configurable levels of accuracy or even the possibility to use a fixed location.

Change Geolocation (Location Guard)

Change Geolocation (Location Guard) is a browser addon that let you easily change your geographic location to a desired value and protect your privacy.

Simply open addon's option page and set latitude and longitude for where you want the geolocation to be (default location is Greenwich, UK). Next, reload a page and check your location (i.e. webbrowsertools.com/geolocation/). Please note that, beside latitude and longitude you can set other variables in geolocation API (see options page). Moreover, pressing on the toolbar icon will activate or deactivate the addon.

Note: toolbar button serves as ON|OFF switch to activate and deactivate the addon. Green color is for ON and grey color is for OFF state.

Link Alert

Displays an icon in the tooltip or next to the cursor indicating the target of a link. May warn you when the target element is not what the description says, e.g. you expect a .png file but there's an .exe file in the link.

Google Search Link Fix

This extension prevents Google and Yandex search pages from modifying search result links when you click them. This is useful when copying links but it also helps privacy by preventing the search engines from recording your clicks.

Attention! You should avoid Google search and use DuckDuckGo instead!

History AutoDelete

This WebExtension enhances your control of history. Letting you choose which domain to be blacklisted from history. In addition, you can choose to clear older history entries by X amount of days.

Forget Button

Quickly delete your browser history, cookies, cache, downloads, forms, and passwords

Luminous: JavaScript events blocker

An extension to identify, analyze and block code execution and event collection through JavaScript in your browser.

Personally I do not use this one.

ClearURLs

This add-on will remove the tracking fields form all URLs which are visited by the browser. We use an external rule file which is regularly updated by us and which you can find here.

Skip Redirect

Some web pages use intermediary pages before redirecting to a final page. This add-on tries to extract the final url from the intermediary url and goes there straight away if successful.

Universal Bypass

Universal Bypass has bypasses for sites which make you wait (Adf.ly, Adfoc.us, Shorte.st, etc.), sites which make you do something (sub2unlock.com, etc.) and even trackers (Bit.ly, Goo.gl, T.co, etc.). Plus, you can write custom bypasses.

WebAPI Manager

This extension allows users to selectively allow different hosts on the web to have access to different types of browser functionality. Doing so allows security and privacy sensitive web users to limit the attack surface presented to websites, and to limit websites to the functionality they actually need to carry out user-serving purposes.

Authenticator

Authenticator generates two-factor authentication (2FA) codes in your browser. Use it to add an extra layer of security to your online accounts.

Always keep a backup of your secrets in a safe location. Encrypting your secrets is strongly recommended, especially if you are logged into a Firefox account.

Features: - Add accounts by scanning QR codes
- Search your accounts by pressing "/"
- Translated into more than ten languages
- Encrypt your secrets with a password
- Backup your secrets to a file, Google Drive, or Dropbox
- Sync your secrets with your Firefox Account
- Open source

Permissions: - "Access your data for all websites" - Needed to take screenshots for scanning QR codes
- "Input data to the clipboard" - Needed to copy codes when clicked

Supports: - TOTP
- HOTP
- Steam Guard
- Blizzard Authenticator

Bloody Vikings

Bloody Vikings! simplifies the use of temporary email addresses, helping you to protect your real address from spam and to stay anonymous.

Instead of exposing your real email address to every random site asking for it, simply right-click on the designated input field and select "Bloody Vikings!". Bloody Vikings! automatically inserts a temporary email address and opens the corresponding mailbox in a new background tab.

nBox

nBox generates for you an email address for each site, for free. - Effortlessly thanks to our browser extensions
- Addresses are anonymous and private
- Delete the addresses you don't want any more
- Be notified according to your preferences on each email

To use it you must create an nBox account.

Redirect AMP to HTML

Automatically redirects any Accelerated Mobile Page (AMP) pages to their regular HTML equivalent.

When you see an AMP page, you're likely seeing a page served directly by Bing or Google who can suck in information about what you do on that page. Keep the web decentralized and say “No!” to search engines that want to take control over the web.

AMP pages are designed for small-screen devices and often don't translate well to larger screens. The extension can be especially useful if you receive links from people who're on their mobile devices while you're on your desktop computer.

FireX Proxy

FireX Proxy allows you to change your IP address. The proxy list updates about every minute.

Useful when you are trying to reach a destination webpage from a different IP and you do not have a VPN.

Warning! Please not that when you connect to any of the proxies offered, you have to trust its provider. It is not recommended to log into any account when connected to a proxy.

Permission Inspector

Missing permissions inspector for Firefox - Snapshot of all the permissions used by each installed extension.

Add-ons are powerful tools which can modify the browser using various features allowed by browser. While installing an add-on there is a permission prompt which tells what all features will be accessed by the add-on. Post that we have no way to know what an installed add-on is accessing. Permission inspector bridges this gap and shows what all an add-on can do to the browser.

There are two views for this add-on

Extension-wise: Shows permissions for each add-on
Permission-wise: Shows add-ons using each permission.

Zoom Redirector

Zoom Redirector transparently redirects any meeting links to use Zoom's browser based web client.

Productivity

Brief

Brief makes reading RSS feeds as easy and intuitive as it gets. Designed to have exactly the right set of features, it is powerful and simple at the same time. Feeds are presented on a seamless, interactive page which let's you bookmark and tag items with a single click.

Here you can find a custom dark theme for Brief.

There's also Smart RSS Reader, which is an actively developed alternative to Brief.

To convert some popular proprietary news feeds like YouTube channels or Twitter feeds into a RSS feeds, you can use RSS Box or RSS.app.

Personally I use QuiteRSS, because Brief causes Firefox to freeze when processing a large number of feeds and has some problems with YouTube feeds which are refreshed several times after being marked as read.

Fraidycat

Fraidycat is a browser extension for following folks on a variety of platforms. But rather than showing you a traditional 'inbox' or 'feed' view of all the incoming posts - Fraidycat braces itself against this unbridled firehose! - you are shown an overview of who is active and a brief summary of their activity.

There are no fancy algorithms behind Fraidycat - everything is organized by recency. (Although, you can sort follows into tags and priority - "do I want to track this person in real-time? Is this a band that I am only interested in checking in on once a year?") For once, the point isn't for the tool to discern your intent from your behavior; the point is for you to wield the tool, as if you are a rather capable kind of human being.

Feeds (RSS, Atom or JSON Feed). This is how Fraidycat reads blogs, Tumblr, Medium, Mastodon, micro.blog, Wikipedia, Kickstarter or Stack Overflow. If only every network used RSS!

Twitter, Instagram, SoundCloud. These sites don't support RSS, so Fraidycat does its best to pick things out of their web pages.

Pinboard, YouTube and Reddit. These sites do offer RSS, but it's not advertised very well. So Fraidycat figures out where to find the RSS feeds for you.

Twitch. Fraidycat now also shows when a follow is live.

TiddlyWiki. Fraidycat reads the whole wiki and treats it like a giant RSS feed. Be aware that giant wikis may load down Fraidycat.

Fraidycat is available also as a separate app.

Quick Dial

Quick Dial, a speed dial page inspired from fast dial. Full Open Source, No Web Service, No Cloud Account.

This is the best SpeedDial extension out there. There are some better looking (by default only, because you can customize this one in any imaginable way), but a lot of them are a privacy nightmare that collects multitude of user data.

NOTE: Currently Quick Dial does not work properly when uMatrix, Privacy Possum or Print Edit WE extension is installed.

Perfect Home

Replace your new-tab page and home page with your bookmarks. No ads, no speed dials, no frequently visited or other "frecence" bullshit! Just your own, predictable grid of links.

Features: - Only 1 permission: bookmarks - Drag & drop tiles to reorder - Custom images for tiles (right-click on a tile -> custom thumbnail) - Command palette - filter flat list of all bookmarks (currently Cmd+P on mac - when focus is on page) - Docked folders! - show your "Read later" or "TODO" on the main page - Style page with custom css - paste your css in settings - Import/export settings and thumbnails to a file, for backup.

FoxyTab

Collection of Tab Related Actions e.g. Duplicate, Close Duplicates, Close to the Left, Copy Title, Merge Windows, Save as PDF, Copy Urls Tab/All/Left/Right, Host keep/close/close other, Sort by URL/Title, Asce/Desc, Move, Reload, Reload Timer.

I use it mostly for the flag in the address bar that indicates the servers location.

FoxyImage

FoxyImage is a tiny multi-process extension that adds a number of Image related actions to the Context Menu.

FoxyLink

Collection of Link Related Actions, e.g. Open Selected Links, Copy Selected Links

Tab Session Manager

Save and restore windows and tabs
Manage sessions with name and tags
Auto save when window is closed
Auto save at regular intervals
Import and export sessions

Simple Tab Groups

Simple Tab Groups works across browser instances/windows too. If you select a group in another window, the selected window will jump to the foreground with the chosen group selected. You can even select the specific tab within that group in background browser windows. GIF example

This allows for easy switching between active and pre-loaded tabs across multiple browser windows.

In the options menu you can find a setting which may be a substitute to the Auto Tab Discard extension.

I find this extension to be a superior alternative to the Panorama Tab Groups extension.

Session Alive

Keep your session alive for any website. Install and forget the session timeout messages.

Almost all websites with authentication has a session timeout. If you are inactive in the website for some time then your session may be expired. You need to login again to perform any action in the website.

This extension will keep your session from expiring by reloading your website in the background. This will keep your session alive without manually reloading website even you are inactive in the website for long period of time.

ScrollAnywhere

Scroll Anywhere enables you to drag scrollbar with your middle (or right / left) mouse button without actually touching a scrollbar. Just hold the middle mouse button and move up-down or left-right. You can also change the behavior to simple "grab and drag" style.

Short preview video here (0:12)

Features:

Momentum allows you to throw page to scroll it faster (just like on your phone)
Middle / Right / Left mouse buttons are supported, see the Options page
Auto-disable on specified domains / sub-domains
Grab and drag scroll like on your phone
Multiplier to speed-up or slow down
On key down enable / disable
Custom scrolling icon

Gesturefy

Customizable mouse gesture add-on, which supports over 60 different commands and additional features like rocker and wheel gestures.

Search Multi Tabs

Search Word position across your tabs body or title/url , then list up in sidepanel.

Snap Links Plus

Select a number of links with a rectangle and open them in new tabs. You can also lasso checkboxes to quickly check or uncheck them. Works with radio buttons as well.

Save Page WE

Save a complete web page (as curently displayed) as a single HTML file that can be opened in any browser. Choose which items to save. Define the format of the saved filename. Enter user comments.

Print Page WE

Edit the contents of a web page prior to printing or saving. Elements in the web page can be edited, formatted, hidden or deleted. Unwanted content, such as adverts and sidebars, can easily be removed.

Search Site WE

Search within the current subdomain or within the entire domain, using the toolbar button or context menu.

Behind The Overlay Revival

Some websites will use an overlay to mask its content with a transparent background to force you to read a message before you can see the actual content.

This extension solves this problem by offering you one button to close any overlay on any website you may ever encounter.

Glitter Drag

A drag extension that supports you drag text, links and images then helps you open, copy or search it.

Textarea Cache

This add-on will save automatically the content in textarea or WYSIWYG editor when user is typing. User can recover the saved texts in the cache panel, even the tab or the window is closed unexpectedly.

ContextSearch

Select text and search from the context menu or a tiled popup using any of your installed search engines. Add new search engines with a right-click, edit favicons and query strings.

This is the best context menu extension out there.

Auto Text Expander

Create custom keyboard shortcuts to expand and replace text as you type.

Ever get tired of typing out long email addresses, phrases you frequently use, or just looking to save keystrokes as you type? Well fear not! Auto Text Expander is here to solve that -- kinda like TextExpander for Mac or AutoText for Windows, but installed and synced across Firefox browsers.

This free (and ad-free) extension adds basic javascript to your pages to check if your last set of consecutive keystrokes matches any of any number of custom shortcuts you can define and expands and replaces that text as you type. Save time, typos, and the satisfaction of being extra lazy.

For a global text expander, that works system-wide, take a look at espanso.

uGet Integration

Integrate Mozilla Firefox with uGet download manager. uGet is described in the software section.

Important: Install uget and uget-integrator before installing this add-on to connect with uGet.

InFormEnter+

InFormEnter adds a small blue marker image after the text fields, clicking on which opens the menu for entering into the text field - no typing required. It has profile support, data sync, shortkeys, built-in password generator, сan fill many fields at once.

AutoFormer

AutoFormer+ is a simple form filler. Once entered data could be saved as a template and next time all data will be filling into forms automatically. Also if you want enter some other information in the same form you can click on AutoFormer+ icon in toolbar and select "Save all fields" to save as an another template.

Sticky Notes

Sticky Notes is a Firefox addon that enable Firefox to put sticky to web page.

Each sticky can have memo, and the size and position are changeable.

And sidebar displays the list of stickies, you can jump a selected sticky.

Joplin Web Clipper

Capture and save web pages and screenshots from your browser to the note taking application Joplin. Joplin is described in the software section.

Tab Center Redux

Tab Center Redux allows you to organize your tabs vertically in the browser's sidebar. It aims to be easy to use while mimicking the vanilla Firefox experience.

The extension provides a handful of of settings and allows power-users to customize its appearance completely with CSS code.

FontFace Ninja

Fontface Ninja is a browser extension that let you inspect, try and buy font on any websites.

Favicon Detector

Click the extension button to detect current website's icons.

Support: favicon msapplication-TileImage apple-touch-icon-precomposed apple-touch-icon

DownThemAll!

DownThemAll will help you select, queue, sort and run your downloads faster. It comes with advanced ways to select what links to download, and will remember your previous decisions so that you can queue more downloads with just OneClick!

Advanced users will also like using renaming masks which let you automatically assign names (and even sub-folders within your downloads folder), fast-filtering or even custom, re-usable filters.

DownThemAll is open-source and free. We spend a lot of time making it, and keep spending a lot of time improving it, and even fixing some problems in Firefox itself so DownThemAll! can work even better. We will never add adware, spyware, user tracking or other nasty stuff.

Down Right Now

This extension helps you to download all the links and media you can find on the Web.

When you visit a page, click to DownRightNow to see the content of the page. The content are links, references, images, videos… and other media present on the page.

DownRightNow helps you to select, organize, prioritize and run your downloads in parallel.

How it works?

DownRightNow is composed of two components: a WebExtensions addon for your browser, and a standalone application, that runs on your machine, independently from the browser.

The standalone download manager is available for Windows, Mac OS X and Linux.

Click here to download and install the standalone application:

https://setvisible.github.io/DownZemAll/

or https://github.com/setvisible/DownZemAll/releases/latest

Project History

This extension was inspired by the old DownThemAll Firefox extension, which was said abandoned after Firefox moved to WebExtensions.

This extension provides the same look-and-feel of classic DTA, and more!

Why a standalone application?

This download manager is a standalone application, in order to separate this extension’s life cycle from the browser’s life cycle.

Moreover a standalone manager provides a lot more features, and is not limited to the Firefox browser or WebExtensions API, so we could write easily all the features we want.

Want My RSS

Puts an RSS/Atom subscribe button back in URL bar. Useful when you are using an external RSS application like QuiteRSS.

Update Scanner

Monitors web pages for updates. Useful for websites that don't provide Atom or RSS feeds.

I prefer the next extension on this list that does the same thing: Web Pages Scanner.

Web Pages Scanner

Scan web pages for updates.

Features: - unlimited number of pages
- automatic and manual scanning
- ability to change charset, accuracy, interval between scans
- notifications about detected changes
- easily add pages to scan list
- preview old and new version of page
- sidebar

Sidebery

Manage your tabs and bookmarks in sidebar.

Features
- Vertical layout
- Bookmarks operations
- Contextual Identities management
- Synchronizing containers
- Different proxy settings for each containers
- Creating tabs snapshots for easy recovering
- Light and dark themes - Configurable navigation
- Multiple tabs selection with right mouse button

Buster Captcha Solver

Buster is a Firefox extension which helps you to solve difficult captchas by completing reCAPTCHA audio challenges using automatic speech recognition. Challenges are solved by clicking on the extension button at the bottom of the reCAPTCHA widget.

It is not guaranteed that challenges are always solved, the limitations of the technology need to be considered.

Tabliss

Transform your new tab page to something beautiful, and unique. Choose from our array of background providers, customise it to you, and be rewarded with stunning , new backgrounds every time you open a new tab. Select your favourite widgets for an extra touch. Create your own new tab experience. Completely free, completely customisable. Express yourself with Tabliss.

Other similar extensions which may suit you better are:
- Bonjourr
- Mesmerized
- Wondertab
- CaretTab
- Flowify

Copycat

This extension creates a right-click menu to provide copy functionality. Features:

Copy tab link/link/selection/image as:
- Plaintext
- Markdown
- BBCode
- HTML

This the most comprehensive extension of this kind I was able to find. Very useful if you copy stuff to a Markdown/HTML source.

Copy Selection as Markdown

Copy title, URL, and selection as Markdown. Select text, right click and click the "Copy Selection as Markdown".

Very handy extension, useful especially if you want only to copy stuff as Markdown and do not need other options offered by the Copycat extension.

Forecastfox

Get international weather forecasts from AccuWeather.com and display them in any toolbar or statusbar with this highly customizable and unobtrusive extension.

The best weather forecast extension I have been able to find.

Rooster Todo Manager

Simple todos manager that sits in your browser's sidebar.
Everything broken down into 3 intuitive lists: Today, Scheduled and Someday

Today
✓ Items that you want to address today
✓ Check to mark as complete
✓ Click to edit (description, date, recurrence)
✓ Menu for more actions (edit, delete)

Scheduled
✓ Items set for a certain date
✓ They show up in Today when the time comes
✓ Each item has an action called "Do it today"

Someday
✓ Items you might get done some time in the future
✓ They have no due date
✓ They just sit there doing nothing until you bring them to life

Snooze Tabs

Snooze Tabs help you focus your attention online, whether you want to remove distractions for now or save something for later. Hit the snooze icon to dismiss tabs you don’t want now, and set an alarm to bring them back when you need them.

Text Link

Allows URI texts written in webpages to be loaded by double clicks.

Linkificator

This add-on parses text parts of HTML pages to match hypertext patterns not correctly encoded (i.e. not part of an anchor) and add an anchor to enable a standard mouse click to access the target as specified by the hypertext.

This can be used as an alternative to the Text Link extension.

Link Gopher

Extracts all links from web page, sorts them, removes duplicates, and displays them in a new tab for copy and paste into other systems. Also extracts embedded, referrer-type links in the format http://www.example.com/go?url=http://www.example.com/foo . Also displays a distilled list of unique domain names used in the links.

Markdown Editor for Firefox

The most significant and purest Markdown editor for Firefox. Just write Markdown and see what it looks like as you type.

Markdown Editor for Firefox also comes with one-click HTML conversion, file support and other discreet gems.

Useful when you do not want to start en external Markdown editor for a quick edit. Includes a handy Markdown tutorial.

TextMarker

Highly customizable text highlighter with different colors and save option for later visits.

WebMemex

This extension takes a step towards turning the browser into an offline-first knowledge management tool. It can store snapshots of web pages you visit on your computer by 'freeze-drying' them: removing scripts and thus most interactive behaviour, but inlining all images and stylesheets to let you save the page exactly the way you saw it.

Save for Read Later

This extension allows you to save pages in a list to read later. Very handy, when you have a lot of tabs "for later", but you do not want to clutter your browser. It also minimizes memory usage of Firefox.

What is important - saved links are synced between your devices.

CopyFish

Do you need to extract text from images, videos or PDF? If yes, then the Copyfish free OCR software is for you.

Common reasons to extract text from images are to google it, store it, email it or translate it. Until now, your only option was to retype the text. Copyfish is soooo much faster and more fun.

"Images" come in many forms: photographs, charts, diagrams, screenshots, PDF documents, comics, error messages, memes, Flash and Youtube movies.

You can verify the results in one glance with the extracted text overlay.

Do you need to switch between OCR languages often? You can define "Quick Switch" buttons for up to three languages on the settings page.

UI.Vision RPA

UI.Vision RPA (formerly Kantu) is open-source Robotic Process Automation (RPA) software for task and test automation. It is 3 tools in 1: Visual web browser automation, Selenium IDE and AI-powered desktop automation for Windows, Mac and Linux.

Easy automation for busy people. UI.Vision RPA automates web and desktop apps, so you can focus on your most important work.

UI.Vision RPA is open-source and “lives” in the web browser, but it can do desktop automation as well. It is a universal task and test automation tool that combines the best of classical web automation with modern, AI-powered automation concepts. UI Vision combines 3 powerful tools into one: - Visual Web Automation and UI Testing - Visual Desktop Automation for Windows, Mac and Linux - Selenium IDE++

(API) Integrate with your favorite tools via command line: One of the best UI Vision features for experts is its extensive command line API. This allows you to integrate UI Vision with any application (e. g. Jenkins and other CI/CD tools, task scheduler,...) and any programming or scripting language (e. g. Python or Powershell).

UI Vision web macros can be combined/used with other extensions such as Tampermonkey, Adblock, uBlock, NoScript, Ghostery, Video DownloadHelper, DownThemAll or LastPass.

Timer

Timer is a lite addon that let you easily setup multiple alarms, timers or stopwatch for yourself.

Simply open toolbar popup UI and then choose a desired tab. The first tab is for alarm adjustment. Simply click on the - add a new alarm - button to view the settings page. Then, add a name for the alarm and adjust date, hour and minute and at the end, click on the - save change - button.

Morning Coffee Quantum

The Quantum-compatible version of the old favorite. Morning Coffee Quantum allows you to create lists of daily websites, as well as a list that you visit every day.

Add tabs' websites to your daily reads through the tab context menu, or manage websites directly through the options page.

Click the coffee cup button (or press Ctrl+Shift+O) to get your websites for the day loaded into separate tabs. It's that easy!

PopUp Encyclopedia

Popup Encyclopedia is a blazingly fast dictionary/encyclopedia which can be used to search any word or collection of words. It supports double-click-on-text navigation. Double-click-on-text navigation is a feature by which you can double-click on any text in the popup window to get it's meaning without having to type it again in search box. [ Note: As of Ver 2.2, this feature is only available on the toolbar popup. ]

The features are: - Works offline as a dictionary. - pports word-lemmatization and word-stemming to increase accuracy. - ean and minimalistic UI. - Double-click-on-text navigation. - For keyboard ninjas, ALT + SHIFT + M is the shorcut key.

Vimium-FF

The Hacker's Browser. Vimium provides keyboard shortcuts for navigation and control in the spirit of Vim.

This is a port of the popular Chrome extension to Firefox.

Most stuff works, but the port to Firefox remains a work in progress.

Tridactyl

Replace Firefox's control mechanism with one modelled on Vim.

I cannot say which one of the Vim extensions is better, as I am used to control the browser with a mouse.

Simple Gesture for Android

Simple touch gesture for Android.

Styling

Dark Reader

This eye-care extension enables night mode creating dark themes for websites on the fly. Dark Reader inverts bright colors making them high contrast and easy to read at night.

You can adjust brightness, contrast, sepia filter, dark mode, font settings and ignore-list.

I have tested all of the dark theme extensions available and this one is without a doubt the best available.

Stylus

Redesign your favorite websites with Stylus, an actively developed and community driven userstyles manager. Easily install custom themes from popular online repositories, or create, edit, and manage your own personalized CSS stylesheets.

Midnight Lizard

This extension changes page colors, brightness and contrast to increase readability and brings dark night mode to all websites.

I do not use this one as it is extremely CPU intensive.

Web Enhancement

Absolute Enable Right Click & Copy

Force Enable Right Click & Copy. Features: - Remove Copy Text Protection On All Website
- Force Enable Right Click Button
- Allow Copy And Highlight
- Disable Annoying Dialog Message (Not Able To Copy Content On This Webpage)
- Re-Enable Context Menu
- Include "Absolute Mode" To Force Remove Any Type Of Protection

Bypass Paywalls

Bypass the sites' paywalls.

Google Unlocked

Google Unlocked is an open source Mozilla extension, which unlocks hidden google search results.

The extension scans hidden search results that were censored by Google due to complaints. The tool scans those complaints and extracts the links, returning them back to the search results, all in a matter of seconds.

Attention! You should avoid Google search and use DuckDuckGo instead!

Iridium

Features highlight: - Play your videos in a pop-out window
- Turn off 60fps
- Allow ads only in videos from your subscribed channels
- Blacklist entire channels from your suggestions and search results
- Make the player fill the entire browser with the Fullbrowser mode feature
- Player always visible where you want while reading the comments
- Player always playing while navigating away from the video page
- Reverse any playlist
- Take video screenshots and save them
- View and save the video thumbnail like old times
- Bring back the total number of videos uploaded by the creator
- Use the relative video post time to know quickly how old the video is
- Control comment section visibility

SponsorBlock

SponsorBlock is an extension that will skip over sponsored segments of YouTube videos. SponsorBlock is a crowdsourced browser extension that let's anyone submit the start and end time's of sponsored segments of YouTube videos. Once one person submits this information, everyone else with this extension will skip right over the sponsored segment.

With this extension, you will automatically skip YouTube sponsors.

The extension also features and upvote/downvote system with a weighted random based distribution algorithm.

More information about how it works: https://sponsor.ajay.app

Ageless

With Ageless you can watch age restricted videos on Youtube without signing in. By the push of a button the age restricted video will open in a new tab and you will be able to watch it. Ageless does not work for videos where the video owner has disabled playback on other websites.

This extension is redundant if you have the YouTube Unblocker script installed.

CCaptioner

A very simple extension which purpose is to assign a text track to a HTML5 video element in a web page.

Many HTML5 video players do not offer the ability to import text track for captions/subtitles purpose. The purpose of this extension is to remediate this problem.

When you want to assign a text track to a video element in a web page:

Open the popup menu and click "Assign text track to..."
Move the mouse over the target video element
Click the video element if needed
A file picker will appear
Pick the .srt or .vtt file to use as text track

The video should now render the captions/subtitles of the file you selected.

The content scripts of CCaptioner are injected if and only if you click on its toolbar icon while on a specific web site, and only for that web site. Once the text track is embedded, the content script terminates and should be garbage-collected by your browser's JavaScript engine.

Once a text track has been assigned to a video element on a given page, you can time-shift the text track through CCaptioner's popup panel -- this is useful when the text track is not well synchronized with the video content.

IMDb Plus

User-defined Enhancements for IMDb

Reddit Enhancement Suite

RES is a suite of tools to enhance your reddit browsing experience.

Unreddit

Show removed Reddit comments.

Works on old and new Reddit.

Hacker News Enhancement Suite

A Hacker News extension for Firefox which changes lots of things.

Reddit Comment Highlights

Lightweight and customizable alternative to a feature normally reserved to Reddit gold users. It requires minimal permissions and syncs between browser sessions! It supports RES (Reddit Enhancement Suite) night mode and custom CSS!

NOTICE: The extension is currently broken due to Reddits recent UI redesign.

readReddit

The extension takes text posts or comments and transforms the text from this into something more readable with less distractions like this
Or if you are more into dark themes it will actually look like this
It is even somewhat "smart" about how it grabs the text, so when you encounter one of those authors who didn't have enough space and needed to continue as replies to their original story it will also include the text from those comments! It does this by going over the comments in posting order, picking those made by the author (if there are any) and adding those to the story. It repeats that for child comments until the entire story has been combined.
Features

Works on both old and redesigned reddit.
Has a light and dark mode.
Allows you to choose your own font.
Adjustable font size.
Adjustable text width.
Works on both text posts and comments.

Autopagerize Advanced

A browser Extension for auto loading paginated web pages

ffCK Overlays

It's a simple extension, really. Don't like something you see on a webpage? Right-click it, click "f*ck it", and it'll disappear from your screen.

Nuke Anything Enhanced

A bit richer in features alternative to ffCK Overlays.

Allows you to hide almost anything via context menu 'Remove Object' or 'Remove Selection' with possibility of multiple undo of 'Remove Object'. You can also make a selection and chose "Remove everything else" to clear the page and only leave the selected text.

Other worth mentioning extension that aims to achieve the same effect is boom!.

YouTube Classic

Restore Classic YouTube.

It seems to be easier on resources and sometimes help when the current YouTube design causes Firefox to stutter.

h264ify

Try h264ify if YouTube videos stutter, take up too much CPU, eat battery life, or make your laptop hot.

By default, YouTube streams VP8/VP9 encoded video. However, this can cause problems with less powerful machines because VP8/VP9 is not typically hardware accelerated.

In contrast, H.264 is commonly hardware accelerated by GPUs, which usually means smoother video playback and reduced CPU usage. h264ify makes YouTube stream H.264 videos instead of VP8/VP9 videos.

Don't Fuck with Paste

This add-on stops websites from blocking copy and paste for password fields and other input fields.

Privacy Redirect

Redirects Twitter, YouTube, Instagram, & Google Maps requests to privacy friendly alternatives - Nitter, Invidious, Bibliogram, & OpenStreetMap.

Allows for setting custom instances and toggling all redirects on/off.

You can also use Invidition for Twitter and YouTube redirects.

Netflix Hidden Categories for Firefox

Search and find Netflix's Hidden Categories. Netflix has thousands of hidden categories. This extension helps you unlock many of those secret categories.

Film scores for Netflix

Film scores for Netflix. Add-on enriches netflix browser with a rating based on the scores from FilmWeb.pl, IMDb.com, Metacritic.com, Nflix.pl and TheMovieDB.org sites.

Netflix 1080p

Forces 1080p playback for Netflix. Without this extension Netflix will not allow you to use 1080p quality under Firefox.

Better Netflix

"Better Netflix" adds the following features to Netflix:

Ultrawide display support (21:9 aspect ratio) [To 21:9: '.', to 16:9: ',']
Zoom in and out of the video [Zoom in: '+', zoom out: '-']
Show the elapsed time of the video
Disable mouse movement [Disable: 'd', enable: 'e' or 'Esc']
Statistics [Toggle: 'q']
Menu to select video bitrate (video quality)
Option to automatically select the highest video bitrate available. This option is enabled by default. It can be disabled on the options page (Add-ons → Better Netflix → Preferences).

"Better Netflix" provides the keyboard shortcuts specified in [ ]-brackets of the list above.

Steam Database

Adds Steam Database links on various pages in the Steam Community and Store. Also highlights owned and wished products on steamdb.info

SteamDB is a website (not affiliated with Valve) that lists and tracks information regarding applications and packages available on Steam.

Augmented Steam

Augmented Steam is a Chrome extension that improves your experience on Steam store and Steam Community, by adding more information and customization options.

Please note this is not the original "Enhanced Steam" extension, but a spiritual continuation of the project.

Most notable features:
- shows the best current price from multiple authorized stores on the game's page (see screenshot)
- shows historically lowest price for the game, with a link to the complete price history
- adds a more noticeable DRM warning
- highlights games you already own or have in your wishlist
- adds an option to hide ignored games from the search results
- adds regional price comparison for easier overview of the game's pricing around the world
- adds infinite scrolling to search results
- adds a button to open the game page in the (installed) Steam client
- adds OpenCritic ratings and MetaCritic user score ratings
- shows overview of hours of play time you can get from HowLongToBeat.com
- adds links to other Steam related pages like SteamDb or AStats
- adds overview of the estimated number of players from SteamCharts.com
- lists estimated owner count and average playtime by Steamspy.com

Peek

Peek is a browser extension that lets you preview dozens of types of documents before you download them. Just hover over a file's link, and Peek will display an interactive preview of the file instantly.

Peek can create previews for the following file formats:

- PDF, TXT, RTF documents
- Word Documents (.doc, .docx)
- Excel Documents (.xls, .xlsx)
- PowerPoint Presentations (.ppt, .pptx)
- WebM, MP4, GIFV, and OGG/OGV Video
- MP3 and WAV Audio
- JPEG, PNG, GIF, SVG, PNG, APNG, ICO, and BMP images

Peek can also show documents hosted on Google Docs and Apple iCloud. However, iCloud support is limited to Keynote files, as Apple doesn't allow other documents to be embedded.

2read

Convert article in current tab to readable form and upload it to P2P network (IPFS).

Please note that content shared with this addon is just cached on IPFS servers. If you want to store the content permanently, you need to have IPFS node running on your computer. You can easily install your local IPFS node using one of these desktop clients:

2read will automatically "pin" your content if you have local node running.

IPFS Companion

IPFS is a new hypermedia distribution protocol, addressed by content and identities. IPFS enables the creation of completely distributed applications. It aims to make the web faster, safer, and more open. → Learn more about IPFS

This extension provides a suite of useful features:

Detect requests for IPFS paths and redirect them to a custom gateway
Detect hostnames with DNSLink and redirect them to IPNS at a custom gateway
Monitor peering and gateway status
Inject the IPFS API into every website's javascript context as window.ipfs
Share files by uploading them to IPFS with optional preload at a public gateway
Toggle between Active / Suspend state of all IPFS integrations
Toggle between external HTTP API and experimental in-memory js-ipfs node (via Preferences)
Pin, Open WebUI, Copy Shareable Links…
…and much more!

Other

EpubPress - Read the web offline

EpubPress bundles webpages into an offline book that you can read on any of your devices.

Benefits: - Downloads webpages for offline reading. - Removes ads and banners from webpages for a cleaner reading experience. - Compatible with all your mobile devices (Kindles, Nooks, iPhone, iPad, Android, etc.). - Email delivery, allowing you to push content directly to your device.

All the amazing content of the internet, available on devices that were made for reading!

How to use: 1) Open all your articles in separate tabs. 2) Order them the way you want them to appear in the book. 3) Click 'EpubPress' in your menu bar. 4) Select your articles. 5) Download and enjoy!

Bookmarks Organizer

With the Bookmarks Organizer, it's easy to put order in your bookmarks. The Bookmarks Organizer finds no longer working bookmarks, redirects, duplicates and more.

Keep or Delete Bookmarks

Cleaning up bookmarks is boring. The Firefox add-on Keep or Delete Bookmarks brings some fun to this task by allowing you to sort out the bookmarks like on "Tinder" or similar services.

Plasma Integration

Useful extension for Linux/KDE Plasma users.

Multitask efficiently by controlling browser functions from the desktop, even while Firefox is in the background. Manage audio and video playback, check downloads in the notification area, send files to your phone using KDE Connect and more inside the KDE Plasma Desktop.

The plasma-browser-integration package must be installed for this extension to work. It will be available from your distribution's package manager.

Breeze Duo

The default GTK+3 Breeze theme that improves GTK applications' look under KDE Plasma has some troubles with Firefox. One of this annoying glitches is that the font colour does not have enough contrast with the background, so it is tough to read the tab title.

This theme improves the readability of the tabs titles and uses default colours of the KDE Breeze colour palette, giving a more consistent appearance under KDE Plasma.

Extension Source Viewer

Adds a button to right of the address bar when a Firefox extension is detected. This button shows two options:

Download extension as zip file
View source

Radical

Riot Web bundled as Firefox Add-on.

Features:

Riot Web served entirely locally without the need for additional setup
Ability to edit Riot Web's "config.json" in the Add-on preferences
Search in encrypted rooms using Radical Native

Tips:

Multiple accounts are possible by using containers. Just right-click the riot tab and select "Reopen in Container"
To bookmark the riot tab in a specific container it's possible to use the Open URL in container Add-on, then just add a bookmark in the format: ext+container:name=Container Name&url=moz-extension:///riot/index.html

Bonus Section

Hosts File

In addition to uBlock Origin, which was mentioned at the top, you could go one step further and use custom hosts file to block entire domains which are identified as advertisements, malware, tracking and other malicious code. Moreover it reduces your bandwith use and makes web pages load faster.

The most extensive hosts list is located here: Unified hosts file

To use it follow the instructions below:

For Windows 7 and Vista use "C:\windows\system32\drivers\etc\hosts" or "%systemroot%\system32\drivers\etc\hosts"

For Windows 8 and Windows 10 use "C:\Windows\System32\drivers\etc\hosts".

You may have to use Notepad and "Run as Administrator"

For Linux, Unix, or OS X place this file at "/etc/hosts" or on some systems at "/private/etc/hosts". You will require root access to do this. Saving this file to "~/hosts" will allow you to run something like "sudo cp ~/hosts /etc/hosts".

Firefox Profilemaker

This tool will help you to create a Firefox profile with the defaults you like.

You select which features you want to enable and disable and in the end you get a download link for a zip-file with your profile template. You can for example disable some functions, which send data to Mozilla and Google, or disable several annoying Firefox functions like Mozilla Hello or the Pocket integration.

Each Setting has a short explanation and for the non obvious settings links to resources describing the feature and the possible problems with it.

ShadowFox

ShadowFox was inspired by changes made in Firefox 57, which limited the amount addons could customize both the user interface and "protected" web pages.

This project aims at creating a universal dark theme for Firefox while adhering to the modern design principles set by Mozilla.

ShadowFox styles the entire user interface, protected webpages (such as about: pages and addons.mozilla.org), and over 40 popular addons.

An essential tool for people using dark themed desktops.

Firefox 8K Wallpapers

Four wonderful Firefox wallpapers, each one containing a different variant of FF's logo:

Table of contents:

Hosts File