Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
Flash Video Downloader helps you to download any video (flv, mp4, HD) from YouTube-like, Facebook, Break, Metacafe and more in one click. You can download mp3, music (iPod), avi and more. Download Flash games. Download Helper. 4K download
Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Orkut, and many, many other sites. You can even customize Firefox and other programs themselves.
The Web Developer extension adds various web developer tools to the browser.
Reloads web pages every so many seconds or minutes. The function is accessible via the context menu (menu you get when you right click on a web page) or via tab context menu (right click on the tab)
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
Session Manager saves and restores the state of all or some windows - either when you want it or automatically at startup and after crashes. It can also automatically save the state of open windows individually.
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Fasterfox Lite: Performance and network tweaks for Firefox, without the Enhanced Prefetching. This is a fork from the original "Fasterfox".
StumbleUpon is the easiest way to discover new and interesting photos, videos, web pages and more, recommended by a community of experts. Tell us what you are interested in and we recommend page after page of amazing stuff you’d never expect to see.
An extension to silently generate a TinyURL for your current page at the click of a button. Also shows you where TinyURLs on the web will take you.
Shareaholic is the easiest way to share & bookmark great content from anywhere on the web from one simple ALL-IN-ONE add-on. Works with Facebook, Twitter, Pinterest, Google, LinkedIn, E-mail and 200+ additional services.
This 15KB restartless add-on will add a "File" -> "Restart" menu item and a ctrl/cmd + alt + r hotkey to restart Firefox or Seamonkey.
Collections are groups of related add-ons that anyone can create and share.Explore Collections