Most Popular Extensions
Lightning Requires Restart Featured
Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.
The first and only download manager/accelerator built inside Firefox!
ImportExportTools Requires Restart
Adds some tools to import and export folders and messages
FlashGot Mass Downloader Requires Restart Featured
Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.
Provider for Google Calendar Requires Restart
Allows bidirectional access to Google Calendar
Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.
FireFTP Requires Restart
FireFTP is a free, secure, cross-platform FTP/SFTP client for Waterfox which provides easy and intuitive access to FTP/SFTP servers.
Check out my new project, FireSSH!
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.
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).
User Agent Switcher Requires Restart
The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.
Speed Dial Requires Restart
Direct access to your most visited websites
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
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
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.
NetVideoHunter Requires Restart
This add-on is a downloader that lets you easily download videos from sites like Youtube, Facebook, Metacafe, Dailymotion, Break, VKontakte and music for example from SoundCloud, Grooveshark and from many other sites...
MinimizeToTray revived Requires Restart
Minimizes windows into the system tray.
SQLite Manager Requires Restart
Manage any SQLite database on your computer.
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.
gContactSync Requires Restart
Synchronizes contacts & groups between Thunderbird or SeaMonkey and Google Contacts. Imports Facebook friends, contacts you follow on Twitter, and more.
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!