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.
Provider for Google Calendar Requires Restart
Allows bidirectional access to Google Calendar
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.
Add-ons Manager Context Menu Requires Restart
Add more items to Add-ons Manager context menu.
gContactSync Requires Restart
Synchronizes contacts & groups between Thunderbird or SeaMonkey and Google Contacts. Imports Facebook friends, contacts you follow on Twitter, and more.
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.
ChatZilla Requires Restart
A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.
Send Later Requires Restart
True "Send Later" functionality to schedule the time for sending an email.
Mail Redirect Requires Restart
Allow to redirect (a.k.a. "remail") mail messages to other recipients.
Copy Plain Text 2 Requires Restart
Copies text without formatting
QuickNote Requires Restart
A simple note-taking extension.
Diagnostics tool for Adblock Plus, provides some insight into internal processes of Adblock Plus.
SmartTemplate4 Requires Restart
SmartTemplate4 offers an easy way to automatically create customized replies by auto-inserting various mail headers. Templates can be created for every account as well as for the default (all email accounts). Also supports the Stationery Add-on.
Add-on Update Checker Requires Restart
Adds Tools menu item to check Add-ons for updates. Includes toolbar icon.
Mouse Gestures Suite Requires Restart
Mouse gestures for SeaMonkey & Firefox: navigate & execute commands using mouse gestures (with single mouse button) and rocker gestures (by pressing 2 mouse buttons). Also: scroll wheel navigation, page scrolling, tab scrolling.
AutoCopy 2 Requires Restart
Copies selected text to the clipboard automatically.
PlayFlash 32bit Requires Restart
Flash player plugin - unofficial xpi repack for 32bit browsers.
Use when official plugin installer is not suitable.
All binary files are copyrighted by their authors and distributed for free.
Copy As Plain Text Requires Restart
Removes formatting from copied text.
FiltaQuilla Requires Restart
Adds many new mail filter actions - launch a file, suppress notification, remove star or tag, mark replied or unread, copy as "read", append text to subject.
Highlighter Requires Restart
Quickly highlight some text in Thunderbird message composing windows.