Extensions by Weekly Downloads
Live HTTP Headers Requires Restart
View HTTP headers of a page and while browsing.
MinimizeToTray revived Requires Restart
Minimizes windows into the system tray.
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.
LookOut 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).
Transform the colors of entire web pages or selected elements. Combine predefined themes with basic transforms. Save transforms for specific web domains.
NoRedirect Requires Restart
NoRedirect lets the user take control of HTTP redirects. It can be used to interdict an ISP's DNS search redirection hijacks, preview/screen "shortened" URLs (e.g., TinyURL), stop the annoying redirection of "smart" error pages, etc.
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.
HttpFox Requires Restart
An HTTP analyzer addon for Firefox
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!
DownThemAll! AntiContainer Requires Restart
Make the resources behind container pages easily downloadable by DownThemAll!
AutoProxy Requires Restart
Are you concerned about your privacy? Or, are you blocked from some websites by a firewall? And, are you arming yourself with a proxy? In that case, AutoProxy is designed for you! A tool to help you use your proxy automatically & efficiently.
Torrent Tornado Requires Restart
Simple Locale Switcher Requires Restart
An easier management of the user interface language
Fire IE (FireIE, Enhanced IE) Requires Restart
Embeds Internet Explorer(IE) to use the powerful Firefox add-ons.
Not only an enhanced IE Tab, but also an enhanced Internet Explorer with Adblock Plus and FireGestures support.
Switch to the IE engine in one click and dismiss your IE.
Mail Redirect Requires Restart
Allow to redirect (a.k.a. "remail") mail messages to other recipients.
Complete YouTube Saver Requires Restart
Download YouTube videos in various formats including 1080p, 4K etc (DASH formats). Convert audio track from videos to MP3 or WAV, or save audio in native format (Ogg, AAC/M4A, MP3, OPUS). Save YouTube page, video, comments and subtitles to one folder
If you are the kind of person who likes to have total control over every aspect of your downloads, "Download Status Bar" is the add-on you are looking for.
FireTray Requires Restart
A system tray extension for Linux and Windows, allowing to set up custom icon, hiding to tray instead of closing, display the number of unread messages in mailing applications, and other features ...
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
Cookie Importer Requires Restart
Imports cookies from a textfile.
Reads Netscape standard cookies.txt files as exported by IE and others.
Very useful in combination with the Cookie Exporter add-on.