Remote shell and test-driven development tool for Mozilla developers
You can now autosave messages from TB upon...
The AutoSlide addon automatically moves the splitter between the thread and the message pane in Thundbird so that the thread pane is set to a optimal height.
An extension which provides GnuPG/GPG/PGP related functions to Moizilla Firefox, Thunderbird and Seamonkey
Visual representation of how spam-like messages are.
Personasizer No Restart
Personasizer allows you to expose more of your persona's header image. Useful for personas that have text or an important part of their content cut off by the browser's navigation elements.
Add a button and a menu to open Evernote in tab.
Google+ Tab for Thunderbird
Publish free/busy calendar file (*.ifb) via ftp or to a file. View other people's free/busy info in meeting organizer window. Integrate Thunderbird and Outlook calendars without Exchange server.
You can now temporarily change the from and fcc on...
OpenSearch is a Mozilla Messaging addon that will allow you to search the web from within Thunderbird.
Somewhere between Thunderbird 1.5 and Thunderbird 2 the message search bar disappeared. This extension restores the search bar. Thunderbird 2 and newer only.
Reboot the QuickFilter bar.
Link to tracking sites. (mainly Japanese companies)
You can now modify the Titlebar of TB's main...
Inserts links from local files via drag and drop on the composition window.
A simple week view for Lightning, as in the print layout.
The missing Thunderbird "copy folder" feature! Copy folders or entire POP/IMAP accounts recursively to any location while maintaining folder structure.
This addons gives you a dashboard-style view of your RSS feeds, like iGoogle or Netvibes (widget view). This is an experiment, so it is still very rough. Right now, consider this as a proof-of-concept rather than a real addon.