Killer Add-ons with extended/specific features for power users. If you are looking for themes or security addons you may then check Killer Themes or Security & Privacy Compilation.
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.
Session Manager saves and restores the state of all or some windows - either when you want it or automatically at startup and after crashes. It can also automatically save the state of open windows individually.
Use PDF Download to do whatever you like with PDF files on the Web. Regain control and eliminate browser problems, view PDFs directly in Firefox as HTML, and use the all-new Web-to-PDF toolbar to save and share Web pages as high-quality PDF files.
View HTTP headers of a page and while browsing.
IE Tab - an extension from Taiwan, features: Embedding Internet Explorer in tabs of Mozilla/Firefox...
— Open web pages saved with Internet Explorer or other browsers (MHT)
— Save many tabs, video and audio reliably, in a single ZIP file (MAFF)
— Return to the original site you saved a page from, and more!
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Never lose anything you type into a web form again! Lazarus securely auto-saves all forms as you type, so after a crash, server timeout, or whatever, you can go back to the form, right click, "recover form", and breathe a sigh of relief.
TV Add-on for Firefox - Watch TV directly from your Firefox Browser, 2780 Live TV Channels sorted by country & category, the TV-FOX allow you to watch thousands of TV channels freely available on the internet. powered by the biggest and most up t...
This plugin allows you to check any file you are about to download, any page you are about to visit with online version of Dr.Web anti-virus.
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.
StumbleUpon is the easiest way to discover new and interesting photos, videos, web pages and more, recommended by a community of experts. Tell us what you are interested in and we recommend page after page of amazing stuff you’d never expect to see.
Make any pages' search functionality available in the Search Bar (or "search box")...