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!
Protect your privacy. See who's tracking your web browsing and block them with Ghostery.
The best security you can get in a web browser!
Allow active content to run only from sites you trust, and protect yourself against XSS and Clickjacking attacks.
The Web Developer extension adds various web developer tools to the browser.
This extension allows you to export your saved passwords and disabled login hosts using XML or CSV files that can be imported later.
Advanced Eyedropper, Color Picker, Gradient Generator and other colorful goodies...
FirePHP enables you to log to your Firebug Console using a simple PHP method call.
Not using Firebug 1.9+ on Firefox 8+? See http://firephp.org/
Secure Login is an extension for Firefox integrated password manager.
An extension that allows for the use of dynamic commands in Firefox.