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).
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.
Xmarks is the #1 bookmarking and open tab add-on. Keep your bookmarks, and open tabs backed up and synchronized across computers and browsers. Mobile phones with Premium access. Utilize LastPass to sync passwords!
German Dictionary (new Orthography) for spellchecking in Mozilla products
Personas are free, easy-to-install "skins" for Firefox. Personas Plus extends that built-in functionality to give you even more control and easier access to new, popular, and your own favorite Personas.
Status bar widgets and progress indicators for Firefox 4+
The extension previously known as GooglePreview. Inserts preview images (thumbnails) and popularity ranks of web sites into the Google, Yahoo, Bing and DuckDuckGo search results pages.
Proxy Selector lets you switch local proxies in Firefox.
This extension allows you to execute common commands using mouse gestures, rocker navigation, scroll wheel navigation and page...
Help make Firefox better. The Add-on Compatibility Reporter enables you to report if the Firefox add-ons that you're using are working properly.
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.
Bypass compulsory web registration with the context menu via www.bugmenot.com.
Collections are groups of related add-ons that anyone can create and share.Explore Collections