Most Popular Extensions
VKontakte.ru Downloader (music/videos/photos @ VK) Requires Restart
Download music, videos and photos from VK.com / vkontakte.ru. One-click download, natural filenames, displaying file size and bitrate for music, downloading HD video, downloading HQ photos. No spam, no usage of your account, no spyware.
Image Zoom Requires Restart
Adds zoom and rotation functionality for images...
The most efficient blocker for Firefox.
No ads, no tracking, and insanely faster page loads.
gContactSync Requires Restart
Synchronizes contacts & groups between Thunderbird or SeaMonkey and Google Contacts. Imports Facebook friends, contacts you follow on Twitter, and more.
Manages the Remote XUL whitelist to allow websites and local files to load XUL content. For versions compatible with Firefox 41 and lower, see All Versions page below.
Live HTTP Headers Requires Restart
View HTTP headers of a page and while browsing.
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.
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
Saved Password Editor Requires Restart
Adds the ability to create and edit entries in the password manager.
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
ChatZilla Requires Restart
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
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.
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
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.
Send Later Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.
Mail Merge Requires Restart
Mass Mail and Personal Mail
RefControl Requires Restart
Control what gets sent as the HTTP Referer on a per-site basis.
DownThemAll! AntiContainer Requires Restart
Make the resources behind container pages easily downloadable by DownThemAll!
HttpFox Requires Restart
An HTTP analyzer addon for Firefox