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 easy way to download and convert Web videos from hundreds of YouTube-like sites.
This works also for audio and picture galleries.
Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.
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.
A customizable mouse gestures extension which enables to execute various commands and user scripts with six types of gestures.
The greatest user script engine on the Internet (a fork of Greasemonkey).
Tweak Network will speed up the loading of web pages and increase the maximum number of simultaneous downloads from a site.
Secure Login is an extension for Firefox integrated password manager.
Allows URI texts written in webpages to be loaded by double clicks.
More Advanced (hidden) configures
Add more items to Add-ons Manager context menu.