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.
IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox...
View HTTP headers of a page and while browsing.
Draw a ruler across any webpage to check the width, height, or alignment of page elements in pixels.
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Set Default FullZoom Level,
Toolbar buttons for Page zoom and Text zoom.
RAMBack will cause Firefox to issue an internal notification to free up memory that is otherwise held for performance purposes. Additional items will be hooked into this notification in the future.
S3Fox Organizer helps you organize/manage/store your files on Amazon S3. It is easy to install and use as it is integrated into the browser.
***New version 0.7 compatible with Firefox 18 is released on the website http://www.s3fox.net
Cookie Editor that allows you add and edit "session" and saved...
Firefox 3 comptible
Tab grouping, vertical tab tree, multi-rows, and various tweaks for power users.
Collections are groups of related add-ons that anyone can create and share.Explore Collections