Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.
ImportExportTools Requires Restart
Adds some tools to import and export folders and messages
Provider for Google Calendar Requires Restart
Allows bidirectional access to Google Calendar
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.
MinimizeToTray revived Requires Restart
Minimizes windows into the system tray.
SQLite Manager Requires Restart
Manage any SQLite database on your computer.
Extra Folder Columns Requires Restart
This extension is for those TB3 users who want the multiple-columns view that TB2 allowed
IMPORTANT: If you are using Thunderbird 38 or later, uninstall this addon. The functionality is in core now.
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.
Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.
As of Firefox 33, Venkman *no longer works*, as the APIs which it needs have been removed.
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.
Quicktext Requires Restart
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
Signature Switch Requires Restart
Switch the signature on/off or choose a new one from your predefined set...
FoxClocks shows times around the world - or just your local time - at the bottom of your browser. It deals with daylight saving time so you don't have to.
Google Calendar Tab Requires Restart
Adds the Google Calendar web interface as a new tab directly into Thunderbird. Creating and viewing events works just as it would in a browser like Firefox
Exif Viewer Requires Restart
Displays the Exif and IPTC data in local and remote JPEG images.
ProfileSwitcher Requires Restart
It adds some options to launch easily other profiles and the Profile Manager.
Copy Plain Text 2 Requires Restart
Copies text without formatting
Mail Redirect Requires Restart Featured
Allow to redirect (a.k.a. "remail") mail messages to other recipients.