Firefox is the best thing that has happened to the Internet for a long time. Firefox with its plethora of Addons has made browsing the web more fun and interactive than it was ever before, all thanks to Firefox. While there have been many resources telling you about must have Firefox Addons, I decided to write a list of Every Firefox Addon I have heard of and used so that you can find the addon that you are looking for very easily. And the result of all this, is this Mega List of Firefox Addons having exactly 222 Addons for just about everything you’d want to do on the Web today.

Advertising

• Block Flash ads/content : Flashblock2. Block ads on webpages : Adblock Plus
• Block ads on webpages : Adblock Plus
• Automatically update adblocker filters : Adblock Filterset.G Updater
  

  Archive/History

• See thumbnails of pages in session history : Reveal
• Create a log of browsing history : Slogger
• See sites visited today/yesterday/2 days ago/etc : History Menu
  

  Blogging

• Blog to LiveJournal/etc : Deepest Sender
• Know when blog content is under Creative Commons license : mozCC
• Blog about the current page : Scribefire for Firefox
• Blog to Blogger service : BlogThis
• Comment about the blog page : coComment
  

  Bookmarking

• Sync Firefox bookmarks on different computers : Bookmarks Synchronizer
• Bookmark at del.icio.us : Bookmark with Del.icio.us
• Bookmark at furl.net : Furl Tools
• Store and sync bookmarks online : Chipmark
• Edit bookmarks easily : Flat Bookmark Editing
• Search the bookmarks : Locate in Bookmark Folders
• Bypass/customize the add-bookmark dialog : OpenBook
• Store and sync bookmarks online : Foxmarks Bookmark Synchronizer
• Sync del.icio.us and Firefox bookmarks : Foxylicious
• Add a bookmark-here link in the bookmarks tree : Add Bookmark Here
  

  Chat

• Chat on the Internet Relay Chat (IRC) : ChatZilla
  

  Clips/Notes/Scrapbook

• Write a note about a webpage : QuickNote
• Save a webpage : ScrapBook
• Save clips from web pages : Clipmarks
  

  Customizing/Editing Website Display

• Customize a page and save as GreaseMonkey script : platypus
• Manage user styles for sites : Stylish
• Add/remove/change some features for sites : Aardvark
• Add/remove/change some features for sites : GreaseMonkey
  

  Discover

• See useful sites for pages geographically marked with ICBM/geo.position tags : GeoURL
• Discover new sites being recommended by others : StumbleUpon
  

  Downloading/Files/FTP

• Automatically save downloads to different directories : Download Sort
• Download all the links on a page (filter by type) : DownThemAll!
• Download/upload files using FTP : FireFTP
• Manage file downloads : FlashGot
• Open the download manager in another tab : Download Manager Tweak
• See download speed in a Status Bar : Download Statusbar
• Stop opening blank windows for downloads : Disable Targets For Downloads
  

  Email/Gmail/Webmail

• Manage multiple Gmail accounts : Gmail Manager
• Email the entire webpage : Amazing webpage emailer
• Treat plain text email address as link : text/plain
• Insert smiley icons in messages : Smiley Xtra
• Use webmail when mailto: link is clicked : WebMailCompose
• Insert custom signature into emails : Signature
• Use different Gmail accounts in different tabs : CookiePie
• Use disposable email addresses : Create disposable email addresses
• Be notified when new mail arrives at Gmail account : Gmail Notifier
  

  Financial/Stocks

• See prices in different currencies : ViewMyCurrency
• See stock prices in a ticker : StockTicker
  

  Google

• Add more links to Google search; remove ads : CustomizeGoogle
• Search Google and use other Google services : Google Toolbar for Firefox
• Display my Adsense earnings : Adsense Notifier
• View an unavailable page via Google archive : Cacheout!
  

  Internet Explorer

• View an Internet-Explorer-only webpage in Firefox : IE Tab
• View the same page in Firefox when it is open in Internet Explorer : FirefoxView
  

  Images/Graphics/Maps/Video

• Map an address; get directions : Map+ i>Click on Google images thumbnail to get full image : Google Images Re-Linker
• Zoom in/out on an image : Image Zoom
• Save video of a URL in clipboard : Clipboard-Save-As
• Show ALT attribute in a popup bubble : Popup ALT Attribute
• Save background/un-save-able images on various sites : Background Image Saver
• Save all the images/media on a page : Magpie
  

  Links

• Copy the anchor text of a link : Copy Link Name
• Double click on plain text url to open it : Text Link
• See small icons to show different link types (secured, pdf etc) : TargetAlert
• Copy the anchor text of a link : Copy Link Text(CoLT)
• Download/open all/selected links on a page : Linky
• Treat a plain text url as a link : Fetch Text URL
• Treat a plain text url as a link : Linkification
• Select and open multiple links in one action : Open Selected Links
• Number the links and use the keyboard to navigate : Numbered Links
• Drag a link or picture and open it in a new tab : Super DragAndGo
• Wrap long links that require side scroll : MR Tech Link Wrapper
  

  Managing Extensions

  
  

  
  

• Sort the extensions list : Slim Extension List
• List installed extensions and themes : ListZilla
• Restart Firefox with one click : Restart Firefox
• List installed extensions and themes : InfoLister
• Backup all Extensions and themes : Compact Library Extension Organizer
• Edit extensions options from Tools menu : Options Menu
• Install and manage extensions locally : MR Tech Local Install
• See updates available for extensions : Update Notifier
• Backup installed extensions : Firefox Extension Backup Extension
  

  Mouse

• Use mouse gestures (auto/history/tab scrollers etc) : All-in-One Gestures
  

  Music

• Control iTunes or Winamp using Firefox : FoxyTunes
• Launch windows media player for embedded video : MediaPlayerConnectivity
  

  PDF

• Open PDF files in a new tab : PDF Download
  

  Passwords

• Remember my username and passwords on sites : Always Remember Password
• Create new different passwords for different sites : PasswordMaker
• Bypass mandatory registration of username and password for sites : BugMeNot
  

  Performance/Speed/Tuning

• See page loading statistics in a statusbar : Extended Statusbar
• Edit/delete/move the menu items : Menu Editor
• Use colorful menu icons : CuteMenus – Crystal SVG
• See page loading progress bar : Fission
• Edit userChrome.css/userContent.css/user.js : chromEdit
• Make the stop and reload button act as one button : Stop-or-Reload Button
• Minimize Firefox to system tray : MinimizeToTray
• Speed up Firefox : Fasterfox
  

  Print

• Remove unwanted text/image block before printing a page : Nuke Anything Enhanced
  

  Privacy

• Use multiple proxy sites to surf the web : SwitchProxy Tool
• Block phishing sites : NetcraftToolbar
• Clear the cache with one click on the toolbar : Clear Cache Button
• See where form information is being submitted : FormFox
• Use multiple proxy sites to surf the web : xyzproxy
• Surf the web without leaving a trace in my computer : Stealther
• Logon to Multiple Email Accounts and other services : CookieSwap
• Clear everything after the browsing session : X (Paranoia) Mod 0.6.5
• Add/edit cookies : Add N Edit Cookies
  

  Productivity

  
  

  
  

• Create a tiny url : TinyUrl Creator
• Add bookmarks to history to make auto-complete URL : AutoMarks
• Navigate up one folder level on a site : Uppity
• Automatically reload a page every few seconds : Reload Every
• Automatically show/close the sidebar with mouse motion : Optimoz Tweaks
• Add more search engines to Firefox search box : Mycroft
• Add a powerful multi-functional preference bar : PrefBar
• See all open tabs together on screen : Firefox Showcase
• Drag a link to a text area : DragToScroll
• Enhance search engine results with more information : BetterSearch
• Disable the install default countdown delay : MR Tech Disable XPI Install Delay
• Open links/mailto with external applications : Launchy
• Use a calendar : Crash Recovery
• Use keyboard to go to next page/previous page : NextPlease!
• Remove content from pages permanently : Remove It Permanently
• See date and day in the status bar : Statusbar Clock
• See more search result/image entries on pages : repagination
• Use the keyboard for more functions : mozless
• Track time spent browsing / on a project : TimeTracker
• Restore the browser exactly as closed last time : SessionSaver
• Use a sidebar to control multiple functions : All-in-One Sidebar
• Switch between multiple sidebars : All-In-One Sidebar
• Smoothly scroll up/down the page : SmoothWheel
  

  RSS/Feeds/Livemarks

• Scroll LiveMarks feeds in a tickler : RSS Ticker
• Read RSS feeds : Sage
• Reload all LiveMarks : Reliby
• Read RSS feeds : Wizz RSS News Reader
• Add RSS feeds to web-based/desktop readers or reader extensions : LiveLines
• See newsfeeds/blogs raw xml with styles : Feedview
  

  Search

• Delete a search plugin : SearchPluginHacks
• Automatically resize the search box for longer terms : Searchbar Autosizer
• Search 1-25 custom chosen sites : Roll your Own Search for Firefox
• Preview thumbnails of search results in Google/Yahoo/etc : GooglePreview
• Choose from a list of search engines : Hyperwords
• Choose from a list of search engines : Groowe Search Toolbar
• Preview thumbnails of search results in Google/Yahoo/etc : Cooliris Previews
• Change the order of search engines : Search Engine Ordering
• Add search engines to context menu : ConQuery
• Search via contextmenu thru customized bookmark keywords : SmartSearch
  

  Search Engine Optimization

• See information about the site : About This Site
• See Google Pagerank in statusbar : Google Pagerank Status
• See search engine link counts and ranks for the page : SEO Links
• See Alexa information, search engine backlinks for a page : SearchStatus
• See search engine backlinks, analyze links, keyword density etc : SEOpen
  

  Security

• Manage cookies : CookieCuller
• Control more javascript options : JavaScript Options
• Allow javascript/java/plugins/etc only on trusted sites : NoScript
• See cookie information on page dialog : View Cookies
  

  Tabs

• Toggle the tab bar via chosen key : HideTabBar
• Use multiple tab rows : superT
• Manage tabs (add/move/etc) : Tabbrowser Preferences
• Manage tabs (multiple links/duplicate/close same domain/etc ) : Tab Mix Plus
• Undo/reopen the tab I just closed : Undoclosetab
• Move to next/previous tab via keyboard : SwiftTabs
• Marks some tabs as permanent : PermaTabs
• Change colors for different tabs : Colorful Tabs
• Duplicate a tab : Duplicate Tab
  

  Text (Copy/Cut/Paste/Spell/Translate)

• Fill web forms with name/address/email etc : Autofill
• Paste a url and load the page in one step : Paste and Go
• Translate selected text using google translation service : gTranslate
• Fill web forms with name/address/email etc : InFormEnter
• Find the selected word with search plugins : Context Search
• Find the meaning of selected word in a dictionary : Dictionary Tooltip
• Find the meaning of selected word from Google definitions : Inline Google Definitions
• Automatically copy the selected text to clipboard : AutoCopy
• Resize text areas in forums : Resizeable Textarea
• Find the meaning of selected word in a dictionary : DictionarySearch
• Highlight a paragraph and navigate with keys : Paragrasp
• Highlight every instance of a word/phrase on the page : Context Highlight
• Increase/decrease/back-to-normal text size of the page : Text size toolbar
• Copy plain text (without formatting/html) : Copy Plain Text
• See all tabs in one window : Viamatic foXpose
• Spell check text in form fields : SpellBound
• Write in WYSIWYG mode in a text area : Xinha Here!
  

  Weather

• See weather information : ForecastFox
• See weather information (+ radar images) : Forecastfox Enhanced
  

  Web Development

• Download an entire website : SpiderZilla
• Find the color code of a given pixel : Show Anchors
• See errors categorizxed by type : Console2
• Capture screenshots : ScreenGrab!
• Check the validity of links on a page : LinkChecker
• Copy and format selected text/title/url : Copy URL+
• Debug ajax/css/html/javascript : FireBug
• Debug javascript : JavaScript Debugger
• Write lorem ipsum content for test page : LoremIpsum Content Generator
• See cookie information for a page : View Cookies
• Change user agent for certain sites : User Agent Switcher
• Find whois information of the site : domainFinder
• Inspect the DOM of HTML, XUL, and XML pages : DOM Inspector
• Inspect the selected element with DOM Inspector : InspectThis
• Measure pixel width with a ruler : MeasureIt
• Modify http/https headers and post parameters : Tamper Data
• Preview the Adsense ads that might be shown on a page : Adsense Preview
• Run automated tests on a site : TestGen4Web
• Edit CSS stylesheet : EditCSS
• Analyze Website Performance : YSlow!
• View source with an external app : ViewSourceWith
• See Xpath information : XPather
• See current page’s heading structure in a sidebar : Document Map
• See IP address of the site : ShowIP
• Validate html : HTML Validator
• See how a page will look on mobile screen : Small Screen Rendering XPI
• See http headers of a page : Header Monitor
• See color contrast page information : Colour Contrast Analyser
• See web development references in a sidebar : DevBoi
• See GET and POST parmeters of the page : UrlParams
• Simulate WAP browsing by viewing WML : wmlbrowser
• Test nightly versions of Firefox : Nightly Tester Tools
• View css styles; view html in another app; validate css/html : Web Developer
• View page html source constructs directly on the page : X-Ray
• View rendered source : View Source Chart
• Capture screenshots : Pearl Crescent Page Saver

If you have anything to add to this list please let me know in the comments section. Pour your heart out and help me build the single largest Firefox Addons list, a List that has addons that is actually useful than filled with all kinds of crap.