Most Popular Extensions
Live HTTP Headers Requires Restart
View HTTP headers of a page and while browsing.
Image Zoom Requires Restart
Adds zoom and rotation functionality for images...
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.
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.
The most efficient blocker for Firefox.
No ads, no tracking, and insanely faster page loads.
Add-ons Manager Context Menu Requires Restart
Add more items to Add-ons Manager context menu.
Send Later Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
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.
Mail Merge Requires Restart
Mass Mail and Personal Mail
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.
LookOut (fix version) Requires Restart
LookOut is a plugin which allows Thunderbird to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).
Support: Thunderbird and SeaMonkey
InlineDisposition changes the disposition of Content-Disposition response headers from attachment to inline; this prevents servers from forcing the browser to save a file and allows that file to be viewed in the browser, if the browser supports it.
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
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.
RefControl Requires Restart
Control what gets sent as the HTTP Referer on a per-site basis.
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
Get a faster browsing experience by blocking nasty web resources using Bluhell Firewall, the lightweight Ad-Blocker and Tracking/Privacy Protector.
IE View Requires Restart
Lets you load pages in IE with a single right-click, or mark certain sites to *always* load in IE.