List of Firefox extensions

Official

• ChatZilla – a full-fledged Internet Relay Chat client that works inside Firefox.
• DOM Inspector – for web developers. It allows them to inspect the Document Object Model tree of any page.

  Website integration

• Forecastfox Weather – displays a summary of weather forecast from AccuWeather.
• LibX – library catalogues.
• StumbleUpon – allows users to encounter random sites based upon the rating given by stumblers and their interests.

  Social addons

• WiseStamp – social profiles and apps for emails

  Google integration

• Google Earth – provides full integration of Google Earth into the browser.
• Google Toolbar – provides features related to Google Search as a toolbar.

  Wikipedia integration

• Universal Edit Button – notifies user when a web page contains editable content.

  Application integration

• FlashGot – provides download features and integration with a variety of external download managers.
• FoxyTunes – controls external media players.

  Browser features

Browser behavior and navigation

• Automatik Text Reader – a multi-language text-to-speech extension.
• Cooliris – a tool for browsing photos and videos from the web or a desktop.
• Flashblock – until 2013, the tool used to prevent downloaded Flash content from displaying unless explicitly started or whitelisted.
• Hyperwords – allows users to select text and perform rich commands, such as instant Wikipedia look-ups, in-page translations, conversions, etc.
• Lightbeam – displays third party tracking cookies placed on the user's computer while visiting various websites with graph.
• Pentadactyl and Vimperator – make Firefox feel and behave like the Vim text editor.
• Turn Off the Lights – is used to obscure or mask content other than a running video.
• Zotero – enables users to collect, manage, and cite research from all types of sources from the browser.

  Bookmarks

• ScrapBook – adds enhanced scrapbooking, page saving, bookmarking, and notetaking functionality.
• Xmarks Sync – adds online bookmark and password synchronization, as well as bookmark tagging and suggested sites.

  Customization

• Greasemonkey – allows users to install user scripts that modify specific web pages
• iMacros – a macro recorder for the Firefox web browser.
• Stylish – allows the user to install custom CSS that can modify specific web pages and XUL application interfaces.

  Download management

• DownThemAll! – a download manager and accelerator.
• Video DownloadHelper – used to download videos from sites like YouTube or Metacafe.

  Feeds

• Morning Coffee – a news displayer.
• Operator – parses microformats.
• Sage – a lightweight feed reader extension.

  Language tools

• Tong Wen Tang – converts Chinese-language web pages between Traditional and Simplified Chinese characters.

  Privacy and security

• Adblock – blocking ads and filtering content via a paired blacklist and whitelist.
• Adblock Plus – blocking ads and filtering content via a paired blacklist and whitelist.
• Decentraleyes – serves common content delivery networks and web libraries locally.
• Disconnect, DoNotTrackMe, and Ghostery – advertisement networks and spy cookies blocking; forks of AdBlock Plus
• GNU LibreJS –, detects and blocks non-free and non-trivial JavaScript.
• HTTPS Everywhere – automatically switches to HTTP Secure whenever possible.
• LastPass, 1Password, Bitwarden – password management, portability and security.
• NoScript – allows users to control JavaScript and other potentially executable content.
• Privacy Badger – blocks canvas fingerprinting and blocks advertisements and tracking cookies that do not respect the Do Not Track setting in a user's web browser.
• uBlock Origin – blocking ads and filtering content via a paired blacklist and whitelist.

Tabs

• Showcase – shows tabs as thumbnails, to preview, manage and search across them.
• Tab Mix Plus – provides tabbed browsing enhancements.

  Website development tools

• Alexa Toolbar – provides access to SEO data.
• ColorZilla – adds an eye dropper, color palettes, page zooming, and displays element information.
• Firebug – allows the debugging, editing, and modifying of any website's CSS, HTML, DOM, and JavaScript, and provides other web development tools.
• FireFTP – is a cross-platform FTP client which provides access to FTP servers.
• Web Developer – adds a menu and a toolbar to the browser with various web developer tools.

  Others

• FireTune – introduced in 2005 which aimed at optimizing the speed of the browser.
• SurfSafe – detects false or misleadingly used images.