Most Popular Extensions
Mozilla Archive Format, with MHT and Faithful Save Requires Restart
— 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!
Lucifox Requires Restart
Read EPUB e-books and browse OPDS catalogs.
Proxy Tool Requires Restart
Proxy Tool - Powerful, yet User-friendly proxy tool to manage your proxies and anonymity needs, including: 46M+ user agents (world's largest), 10 different spoofed HTTP referrers, auto-proxy rotation, plus many more. Developed by http://ProxyList.co
Image Zoom Requires Restart
Adds zoom and rotation functionality for images...
Live HTTP Headers Requires Restart
View HTTP headers of a page and while browsing.
Screengrab (fix version) Requires Restart
Screengrab! saves webpages as images.
New features: upload to internet
Now with 1080p Full-HD Support!
Download every YouTube video you want and you can download them as Full-HD MP4, FLV, 3GP, MP3, M4A and AAC formats. Easy & Fast!
Youtube MP3 Podcaster Requires Restart
Self contained add-on for downloading youtube videos to mp3 for easy listening on podcasting gadgets like a Zune or iPod
Add-ons Manager Context Menu Requires Restart
Add more items to Add-ons Manager context menu.
ChatZilla Requires Restart
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Theme Font & Size Changer lets you change the global font size and font family used for the user interface in Firefox. Design your browser with your favorite font.
DOM Inspector Requires Restart
DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.
Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.
Menu Wizard Requires Restart
Customize menus : Helps removing, moving and renaming menus and menu items
Colorize important menu for ease of use! (use Style (CSS))
Change or disable any of used keyboard shortcuts
Support: Firefox, Thunderbird and SeaMonkey
Thumbnail Zoom Plus Requires Restart
Shows full image when you hover over a thumbnail. Works with Amazon, Baidu Images, Bing Images, Facebook, Flickr, Google+, Google Images, IMDb, LinkedIn, Netflix, Pinterest, Reddit, Twitter, Yandex, YouTube, Wikipedia, Yahoo Images, & many more.
UnMHT allows you to view MHT (MHTML) web archive format files, and save complete web pages, including text and graphics, into a single MHT file in Firefox/SeaMonkey.
gContactSync Requires Restart
Synchronizes contacts & groups between Thunderbird or SeaMonkey and Google Contacts. Imports Facebook friends, contacts you follow on Twitter, and more.