Extensions

Accessibar
Provides various accessibility features such as changing the appearance of web pages, including zoom and color changes, and an integrated text to speech reader.
http://accessibar.mozdev.org/

Accessibility Extensions for Mozilla/Firefox
Toolbar to help users navigate pages, and also tools for developers to check their pages. Installation instructions and documentation.
http://firefox.cita.uiuc.edu/

Adaptive Referer Remover
Blocks referrer URLs from being sent by headers using regular expressions.
http://misccs.dyndns.org/index.php?Adaptive%20Referer%20Remover

Adblock Plus
Blocks advertising, banners and other unwanted stuff on websites.
http://adblockplus.org/

AddArt
Replaces advertising images on web pages with art images from a curated database.
http://www.addart.eyebeam.org/

Add-ons Mirror
Formerly known as The Extensions Mirror. Forum featuring information about a variety of extensions.
http://forum.addonsmirror.net/

All-In-One Sidebar
Helps view dialog windows such as downloads, extensions, and view source or websites in the sidebar.
http://firefox.exxile.net/aios/

AnyColor
Allows users to customize the browser's appearance on the fly.
http://pavlost.wordpress.com/anycolor/

AnyKey
Allows typing into phonetic Russian, Ukrainian, Amharic and others, transforming translit into the chosen language.
http://anykey.mozdev.org/

Arantius - TinyMenu
It merge selected menus for the main menubar into a single menu.
http://trac.arantius.com/wiki/Extensions/TinyMenu

ArchView
It can open and preview archive files on-line ( RAR, ZIP and ISO CD image ) fetching the necessary portions without downloading the whole file.
http://archview.sourceforge.net/

Autocomplete Manager
Provides advanced features for the address Autocomplete component in Firefox.
http://www.leogas.net/acmanager/

AutoCopy
Transfers text to the clipboard as soon as it's highlighted.
http://autocopy.mozdev.org/

Autohide
Autohides the toolbars to make a full fullscreen.
http://www.krickelkrackel.de/autohide/autohide.htm

BabelZilla
International community of translators for Mozilla applications. Includes a system to allow online translations, a list of common extensions terms and tutorials for extension localization in many languages.
http://www.babelzilla.org/

BBComposer
Universal WYSIWYG editor for Firefox, allows edit textareas in those languages: XHTML/CSS, BBCode, Mediawiki, HTML and XBBCode.
http://bbcomposer.elitwork.com/home.html

BlogThis
Adds right-click access to Blogger's BlogThis popup.
http://weblog.philringnalda.com/2004/09/17/updated-right-click-blogthis-for-firefox-and-mozilla

BookmarkDD
It notices when duplicate bookmark is added.
http://bookmarkdd.mozdev.org/

Bookmarks Full Titles
Shows bookmarks full titles in the bookmarks menu and submenus.
http://gkn.interbrainz.com/bookmarksfulltitles/

Bookmarks LinkChecker
Detects updated, redirected and broken links in bookmarks list by adding icons within the drop-down bookmarks menu.
https://addons.mozilla.org/firefox/1647

Bookmarks Synchronizer
Bookmarks Synchronizer is a Mozilla Firefox extension that allows to synchronize bookmarks via an FTP server.
https://addons.mozilla.org/firefox/2367/

Browser Uptime
Report the duration of your current browser session.
http://www.cosmicat.com/extensions/uptime/

Captain Caveman
Personal website of Martijn Kooij, developer of Web Search Pro, PONG! Multiplayer, Grocery List Generator, Quick Locale Switcher and others extensions. Include a forum, news and scores of Football DEV 3 Doorn.
http://www.captaincaveman.nl/

ChatZilla
A simple, straightforward Internet Relay Chat (IRC) client.
http://chatzilla.hacksrus.com/

ChromaTabs
Tints browser tabs with a color specific to the website loaded.
http://labs.mozilla.com/2006/11/chromatabs/

CLiCk, Speak
An open source extension designed for sighted users who want text-to-speech functionality.
http://clickspeak.clcworld.net/

Clickback
Enables back and forward browsing with mouse buttons.
http://www.kirkov.dk/addons/clickback/

Clippings
Saves and manages frequently-entered text for later pasting into forms and input fields.
http://clippings.mozdev.org/

CookiePie
Enables maintaining different cookies storage in different tabs and windows.
http://www.nektra.com/oss/firefox/extensions/cookiepie/

CookieSwap
Maintain multiple cookie profiles and switch between them on the fly.
http://cookieswap.mozdev.org/

Copy Link Text (CoLT)
Makes it easy to copy a hyperlink’s associated text and paste it in several different formats, including user defined formats.
http://www.borngeek.com/firefox/colt/

Copy URL +
Copy to the clipboard the current document's address with additional information.
http://copyurlplus.mozdev.org/

Cusser
Ben Basson's extensions, including Context Highlight, Context Search, Foobar Controls, Image Toolbar, New Tab Homepage and Paste Quote.
http://cusser.net/extensions/

CuteMenus
Adds icons to the most menu-items in pop-ups and menus.
http://cute.mozdev.org/

Deepest Sender
Post to LiveJournal (and LiveJournal based sites) directly from Firefox.
http://deepestsender.mozdev.org/

deskCut
This extension adds desktop shortcut creation to the context-menu. Both Windows and Linux (KDE/GNOME) desktop shortcuts are supported.
http://deskcut.mozdev.org/

Download Statusbar
Allows to keep track of ongoing and completed downloads in a statusbar.
http://downloadstatusbar.mozdev.org/

DownloadHelper
Adds a menu with a list of videos in the current document to easy download.
http://www.downloadhelper.net/

DownThemAll
Download in just one click all the links or images contained in a web page.
http://www.downthemall.net/

Extension Room
Categorized list with details of extensions for Mozilla applications.
http://extensionroom.mozdev.org/

External IP
Allows users to quickly obtain their local public IP address.
http://www.ermodev.se/visa_firefoxExtensions.htm

Fasterfox
Performance and network tweaks for Firefox.
http://fasterfox.mozdev.org/

FaviconizeTab
The width of the specified tab becomes small up to the size of favicon.
https://addons.mozilla.org/firefox/3780

FavLoc
Saves links and images from the context menu to user-defined folders.
http://code.google.com/p/favloc/

/Find Bar/
Adds Regular Expressions to the find bar.
http://www.oxymoronical.com/web/firefox/FindBarRX

Fire Vox
An open source suite of extensions that turn Firefox into a talking browser for the visually impaired.
http://www.firevox.clcworld.net/

Firefox Add-ons
Official list from Mozilla. Add-ons are extensions of the browser that add new functionality to Firefox or change its appearance.
https://addons.mozilla.org/firefox/

Firefox Showcase
Shows tabs as thumbnails, to preview, manage and search across them.
http://showcase.uworks.net/

FirefoxADM
Way of editing centrally managed locked and/or default settings in Firefox via Group Policy and Administrative Templates in Microsoft's Active Directory.
http://firefoxadm.sourceforge.net/

FireFTP
A free, secure, cross-platform FTP client.
http://fireftp.mozdev.org/

FireGPG
Brings an interface to encrypt, decrypt, sign or verify the signature of text using GnuPG.
http://firegpg.tuxfamily.org/

FireMath
A Firefox browser extension for WYSIWYG MathML editing. Site includes installation instructions, usage examples, FAQ, a discussion forum and links to resources.
http://www.firemath.info/

Firesomething
An extension for Mozilla Firefox to change the name in the title-bar and other places randomly.
http://www.cosmicat.com/extensions/firesomething/

Firesort
A graphical utility that can alphabetically sort standard Firefox bookmark files.
http://www.onpubco.com/firesort/

Fission
Combines address bar and progress bar, like Safari.
http://mozilla.zeniko.ch/fission.html

Flashblock
Blocks all Flash content in a web page from loading automatically and allows selective activation and whitelisting of sites.
http://flashblock.mozdev.org/

Foxmarks Bookmark Synchronizer
Automatically synchronizes your bookmarks between two or more computers running Firefox. Includes a feature to access your bookmarks from any computer.
http://www.foxmarks.com/

Glubble
Creates a trusted surfing environment for kids. Allows you to set sites that you trust for your kids, comes with a starter pack.
http://www.glubble.com/

Google Extensions
Includes the Google Toolbar, Google Browser Sync, Google Notebook and Google send to phone.
http://www.google.com/tools/firefox/

Gorgias' Firefox Extensions
A list of Gorgias' Firefox Extensions including: Send To, Permit Cookies, Add Bookmark Here, Focus Last Selected Tab and Tabwarning.
http://gorgias.de/mfe/

Hattrick Livefox
Lets you watch live games of the Hattrick online football game.
http://hattricklivefox.mozdev.org/

Health On the Net (HON)
A collection of Firefox plugins to support the Health On the Net foundation.
http://hon.mozdev.org/

Highlander
Avoids tab duplication by focusing URLs that are already open in another tab.
http://tech.einaregilsson.com/projects/highlander/

How'd I Get Here
Redirects you to the page on which you first clicked a link to the current page.
https://www.squarefree.com/extensions/high/

httpfox
Monitors and analyses all incoming and outgoing HTTP traffic between the browser and the web servers.
http://code.google.com/p/httpfox/

IE Tab
An extension from Taiwan, embeds Internet Explorer in a Mozilla/Firefox tab.
http://ietab.mozdev.org/

iMacros for Firefox
A tool that enables automation of tasks with Firefox.
http://www.iopus.com/imacros/firefox/

InFormEnter
Extension for Mozilla Firefox for form filling in semi-automatic mode.
http://informenter.mozdev.org/

Interclue
Provides a content summary of a webpage when hovering over a link. Including statistics, metadata, sizes and other relevant information.
http://interclue.com/

Javascript Command
Tools for writing/testing javascript on Firefox windows, web pages, and bookmarklets. [Require Login]
https://addons.mozilla.org/firefox/addon/5058

LastTab
Allows tab navigation in a most recently used manner.
http://timothyhumphrey.name/firefox/lasttab.aspx

Launchy
Adds a menu to open different types of links like images, emails, ftp, audio, and video with external applications. Includes overview, customization details, version history and screen-shots.
http://gemal.dk/mozilla/launchy.html

Leak Monitor
Detects one very specific type of leak in chrome JavaScript and in Web pages.
http://dbaron.org/mozilla/leak-monitor/

Link Alert
Changes the cursor to indicate the type and target of a link.
http://linkalert.googlepages.com/

Link Evaluator
Evaluates the availability of on-line resources linked to from a given web page and assesses the response of each URL.
http://evaluator.oclc.org/

Link Widgets
Eases navigation within sequences of pages by providing toolbar buttons for the first, previous, next, and last page.
https://addons.mozilla.org/firefox/2933

Linkification
Converts text links into clickable links.
http://yellow5.us/firefox/linkification/

Linky
Aims to increase the user's power to handle links in Mozilla.
http://gemal.dk/mozilla/linky.html

LiveClick
Enhance Live Bookmarks with links to home pages, favicons, notifications and other feed reading features.
http://liveclick.mozdev.org/

LiveHTTPHeaders
Adds various functions for handling HTTP Headers.
http://livehttpheaders.mozdev.org/

Locationbar²
Puts emphasis on the domain and decodes URLs for better readability.
http://en.design-noir.de/mozilla/locationbar2/

Long Titles
Prevent long tooltips from being cropped by displaying them on several lines.
http://home.etu.unige.ch/~robin0/LongTitles_en.html

Mailfrom
Enables mailto links to be directed to webmail applications for email composition.
http://mailfrom.mozdev.org/

Master Password Timeout
Locks the master security device after a predefined period of inactivity (timeout).
http://www.jetr.com/master_password_timeout/

Memotoo.com for Firefox
Allows to synchronize bookmarks with Memotoo.com and use the Memotoo sidebar and toolbar in Firefox.
http://memotoofirefox.mozdev.org

Menu Editor
Allows you to customize the menus in Firefox and Thunderbird.
http://menueditor.mozdev.org/

Menu Manipulator
Allows you to move, edit, or create new <menu>, <menuitem>, and <menuseparator> elements within a <menubar>, <popup>, or the <tabbrowser>s context menu.
http://forums.mozillazine.org/viewtopic.php?t=272717

Migemo
Provides a feature to find Japanese terms in roman-letter spelling.
http://piro.sakura.ne.jp/xul/_xulmigemo.html.en

Minkaku
Shows you which Firefox Extension is most used. By installing Minkaku you will be able to vote for your installed extensions. Allows searches on database and provides an API.
http://minkaku.goga.co.jp/

Mouse Gestures - Optimoz
Execute commands without using the keyboard, menus or toolbars. Instead, the user holds down a mouse button (usually the right one), moves the mouse in a certain way to form a gesture, then releases the mouse button.
http://optimoz.mozdev.org/gestures/

MozBraille
Self-voicing and Braille output based on the Mozilla browser.
http://mozbraille.mozdev.org/

MozLab
A set of tools and libraries for developers of AJAX and Mozilla applications, packaged as an extension.
http://hyperstruct.net/projects/mozlab

MR Tech Local Install
Provide several tools to install and manage extensions and themes locally.
http://www.mrtech.com/

Multiple Tab Handler
Adds the ability of select multiples tabs at once by dragging the mouse. Features close, reload, bookmark, duplicate tabs or copy URIs commands.
http://piro.sakura.ne.jp/xul/_multipletab.html.en

MultiSidebar
Use multiple sidebars simultaneously.
https://addons.mozilla.org/firefox/4534

NoScript
Blocks all scripts on a page unless it is from a site whitelisted by the user.
http://noscript.net/

Open in browser extension
Allows view different document types within the browser.
http://www.spasche.net/mozilla/

OpenBook
This extension allows for customization of the Add Bookmark dialog. The bookmarks tree can be automatically opened and elements can be hidden. The entire dialog can even be bypassed.
http://www.chuonthis.com/extensions/openbook.php

Organize Status Bar
Add the ability of organize the statusbar icons.
http://yellow5.us/firefox/osb/

Page Zoom Buttons
Ads page zooming buttons to the toolbar for easy access to the full page zoom feature in Firefox 3.
http://www.accessfirefox.org/Page_Zoom_Buttons.php

PageUpdateChecker
Allows the user to monitor a webpage for updates and track changes.
http://pageupdatechecker.mozdev.org/

Paste and Go 2
Useful paste and go, paste and search added to search and location bar context menu.
http://pasteandgo2.mozdev.org/

Piggy Bank
Piggy Bank is an extension to the Firefox web browser that turns it into a “Semantic Web browser.”
http://simile.mit.edu/wiki/Piggy_Bank

POTO Firefox Extensions
Home of the POTO Sidebar extension for Firefox.
http://leon-huang.com/nu/poto.php

Preferential
A simple, accessible GUI that allows the modification of any preference set within the browser environment.
http://preferential.mozdev.org/

ProxyTex Firefox Extension
Allows management of all proxy settings through a simple click on a button.
http://www.idefense.be/firefox/

PsicoTSI Tool
Tool for the on-line game Hattrick. Predicts skill sub-levels using TSI.
http://www.aldeaglobal.net/psicotsi/

Quitomzilla
An extension that aims to help you quit cigarettes while you surf the web or wait for new email.
http://www.quitometro.org/quitomzilla_en.php

RC 's Code Snippets - Firefox & IE - Copy Context Menu Plugin
Adds "Copy As Html" and "Copy As Plain Text" to the context menu.
http://ryanscook.com/adminsBlog/2007/02/firefox-ie-copy-context-menus.html

RefControl
Controls HTTP referrers on a per receiving site basis.
http://www.stardrifter.org/refcontrol/

RefSpoof
Allows you to load pages with a modified referrer.
http://refspoof.mozdev.org/

ReloadEvery
Automatically reloads a web page every so many seconds or minutes.
http://reloadevery.mozdev.org/

Rikaichan
Japanese to English/German/French/Russian dictionary. Automatically de-inflects verbs and adjectives.
http://www.polarcloud.com/rikaichan

Roachfiend.com - How to create Firefox extensions
Long tutorial.
http://roachfiend.com/archives/2004/12/08/how-to-create-firefox-extensions

Router Status
Allows you to control and view the status of your router. Also blocks Internet sites from accessing to the Intranet.
http://www.undermined.org/projects/view/5

Save File to
Save files to user-defined folders and their sub-folders straight from context menu without opening the save dialog.
http://savefileto.mozdev.org/

ScreenGrab!
Save or copy the current page, viewport or selection in a png file.
http://www.screengrab.org/

Scribe
Extension that adds Word Processor like functionality to web forms, including opening and saving form entries as files.
http://prismicspiral.com/scribe/

Secure Login & Autofill Forms
Add-ons to fill out web forms automatically and to login with one click or a keyboard shortcut.
https://blueimp.net/mozilla/

Send Tab URLs
Emails the URIs of all browser tabs.
http://aecreations.mozdev.org/sendtabs/

Server Spy
Displays the brand of web servers in the status-bar.
http://www.jacquet80.eu/mozilla/exts/ServerSpy/

Session Manager
Saves and restores the state of all windows, either when you want it or automatically at startup and after crashes.
http://sessionmanager.mozdev.org/

Shareaholic
An extension to share and bookmark web-pages on popular social sharing and bookmarking services.
http://shareaholic.com/

SiaC - Share-in-a-Click
Share websites you like with your friends, with a click on a toolbar button.
http://www.shareinaclick.com/

Smiley Xtra
Insert smilies from an online database into forum posts, and weblogs.
http://www.smileyxtra.co.uk

Sogame Extensions
Developer site including the extensions: Define, Dummy Lipsum, Extension List Dumper, NewTabURL, searchOnTab, Tab To Window, TimeStamp Converter and withAttach.
http://sogame.awardspace.com/

Sort Tabs By ...
Sorts your tabs by domain/host name or last browsed date, immediately upon navigating to a different URL.
http://codeoptimism.net/blog/post/2007/08/sorttabsby-firefox-extension.aspx

SpiderZilla
Allows to download an entire website from the Internet to a local directory, copying recursively the structure and all the content.
http://spiderzilla.mozdev.org/

Split Browser
Splits the content area of the browser window as you like. Status of split browsers are saved, and automatically restored on the next startup.
http://piro.sakura.ne.jp/xul/_splitbrowser.html.en

Split Pannel
Open panel to left, bottom or right (left, middle, right click) with current URL from Split on context menu.
https://addons.mozilla.org/en-US/firefox/addon/3275

Statusbar Clock
Display the date and time in browser's status bar.
http://www.cosmicat.com/extensions/timestatus/

SubmitToTab
Direct the submission of a form to a new tab.
http://dragtotab.mozdev.org/submittotab/

SwitchProxy
Switch between multiple proxy configurations quickly and easily.
http://mozmonkey.com/switchproxy/

Tab Click Options
Let's you select an action to perform with different clicking events on the tab bar or a tab
http://twanno.mozdev.org/tabclicking/

Tab Groups
Lets a user organize tabs into groups.
http://paranoid-androids.com/tabgroups/

Tab History
Links opened in a new tab retain their session history, cloning the backward history of the tab to all tabs it opens.
http://www.penguinus.com/dev/tab_history/

Tab Kit
Makes tabs more efficient for power users, bringing tab grouping, and tweaks such as multiple rows of tabs or displaying tabs as a tree.
http://jomel.me.uk/software/firefox/tabkit/

Tab Mix Plus
Enhances Firefox's tab browsing capabilities with lots of options.
http://tmp.garyr.net/

Tabinta
Lets insert tab characters in multi-line text input fields.
http://tabinta.mozdev.org/

Tabs Menu
Adds a Tabs menu to the main menu that lets you easily change between open tabs.
http://mikelward.com/software/firefox/tabs-menu

TabSearch
Type keywords, and only the matching tabs will remain showing.
http://www.semicomplete.com/projects/firefox-tabsearch/

Tamil Key
A utility for typing in Tamil language.
https://addons.mozilla.org/firefox/2994

Ted's Mozilla page
Ted's extensions and resources.
http://ted.mielczarek.org/code/mozilla/index.html

Text Formating Toolbar
Allows easy formatting of posts on forums, weblog comments and wikis.
http://codefisher.org/format_toolbar/

ThumbsDown
Bulk image downloader. Downloads the original full size images from a page of thumbnails.
http://thumbsdown.mozdev.org/

Titlebar Tweaks
Tweak browser's titlebar text.
http://www.cosmicat.com/extensions/titletweak/

Torbutton
Allows the user to easily enable or disable the browser's use of Tor, which stands for "the Onion Router", a system providing strong anonymity. Also works with Thunderbird.
http://www.freehaven.net/~squires/torbutton/

Tree Style Tab
This provides tree-style tab bar, like a folder tree of Windows Explorer. New tabs opened from links are automatically attached to the parent tab. If you often use many many tabs, it will help your web browsing because you can understand relations of tabs.
http://piro.sakura.ne.jp/xul/_treestyletab.html.en

TwitterFox
Extension for using Twitter. Shows latest tweets and quick way to enter tweets.
http://twitterfox.net/

Unified Communications
Auto detects phone numbers in web pages and makes the click-to-dial ready with Cisco's Unified Communications Manager. With Cisco Unified Presence Server this also detects people in web text and inserts presence indicators next to them.
https://wwwin.laurenson.com/blog/

User Agent Switcher
Adds a menu to switch the user agent of the browser.
http://chrispederick.com/work/user-agent-switcher/

userChrome.js
Run Javascript like an extension without building a new one.
http://mozilla.zeniko.ch/userchrome.js.html

UserStyles : Stylish
Allow users to create and share custom styles for websites and user interface of Mozilla applications. Includes a collection of customized user styles and a forum.
http://userstyles.org/

Web Panel Enhancer
Add a contextual items related to webpanels and other panel functions.
http://editcss.mozdev.org/indexwpe.html

Wikipedia Toolbar
The Wikipedia extension makes editing of Wikipedia pages easier by adding a new toolbar.
http://wikipedia.mozdev.org/

wmlbrowser
Simulate WAP browsing by viewing WML (Wireless Markup Language) pages in Mozilla Suite, SeaMonkey or Firefox.
http://wmlbrowser.mozdev.org/

XHTML-MP
Allows render HTML content with the mime-type of application/vnd.wap.xhtml+xml.
http://xhtmlmp.mozdev.org/

XPather
Generates XPaths while browsing or inspecting HTML/XML/*ML documents, evaluates XPaths, inspects the results and extracts the content.
http://xpath.alephzarro.com/

X-Ray
Shows the tags on a page without viewing the sourcecode.
http://www.designmeme.com/xray/

Xrl.in Tiny Links
Adds a small button to the URL bar, that let's you copy/paste or e-mail a short URL for the page you are visiting.
http://codefisher.org/projects/xrl.in/

YesScript
Allows blacklist JavaScript from defined domains.
https://addons.mozilla.org/en-US/firefox/addon/4922

Zotero
Firefox extension to aid the collection, management, and use of research sources. Details of features, project news, discussion forums, and download.
http://www.zotero.org/