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).
The first and only download manager/accelerator built inside Firefox!
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!
IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox...
Bypass compulsory web registration with the context menu via www.bugmenot.com.
Get international weather forecasts from AccuWeather.com and display them in any toolbar or statusbar with this highly customizable and unobtrusive extension.
Statusbar button to turn the proxy on and off with a single click.
Allow you to launch embed video of website in an external application with a simple click ...
Sage is a lightweight RSS and Atom feed aggregator extension for Mozilla Firefox. It's got a lot of what you need and not much of what you don't.
Press ctrl+shift+K (or) double-click to see its meaning. This extension is ideal for those who doesn't like to switch their window to see the meaning of a word. ...
Note from Mozilla: This add-on has been discontinued. Try Google Minimalist instead.
CustomizeGoogle enhances Google by adding information and removing unwanted information.