Add-ons

Provider for Google Calendar by Philipp Kewisch

Allows bidirectional access to Google Calendar

FireTray by Foudil, Francesco S., others

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 ...

Collector's Note Not specific to KDE but added here because it works so well in KDE. Only gripe is to restore from tray you have to learn to use mouse wheel rather than having the option of a click or double click.

British English Dictionary by Mark Tyndall

British English Dictionary R1.19 for Firefox, Thunderbird and SeaMonkey by David Bartlett.

To enable, right-click in a multi-line text box, select "Languages", then "English / United Kingdom".

QuickFolders (Tabbed Folders) by Realraven (Axel Grude), Alexander Malfait

The "Swiss army knife" of folders. Turn your favorites into tabs - open folders and subfolders, move mails without scrolling around or searching. powerful + easy.

See new mail at a glance after automatic filtering - supports quickFilters addon!

XNote++ by opto

Persistent sticky notes associated to emails. You can fulltext search with constraints/email them/print/bookmark/copy to clipboard.

If you have a large screen, you can even display the notes outside of TB's main window, so it won't hide anything.

Toolbar Buttons by Button Guy

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.

Tangobird by Haven667

Theme with Tango icons for Thunderbird.

Collector's Note Excellent theme whether you use the Tango project or not. Nice clear tastefully coloured icons.

Folderpane Tools by chuonthis, Philip Chee

Allows for customization of the folder pane. Accounts can be rearranged and the startup folder can be chosen.

Thunderbird Biff by David White

This add-on provides a visual indicator of new Thunderbird mail availability in supported clients (Firefox, Sunbird) and Thunderbird itself. Note: you MUST install this add-on in BOTH Thunderbird and supported clients as there are both client AND ser...

eMarks by Francisco Herrera

Email Bookmarks are here ! ... eMark your important emails.

Do you have an email that will need to revisit/attend later on ? Would you like to keep it handy and get it with a simple click ? Bookmark your important emails with the eMarks addon.

Doodle Plastik for Thunderbird by ogirtd

A childish and colorful theme for Thunderbird with menu icons, and a fresh look inspired by KDE's Plastik interface...

Collector's Note I've not used this myself but if you use the Plastik theme on KDE you will like this.

OxyBird2 by Vimalkumar Velayudhan

An Oxygen icon theme for Thunderbird 3.1 and Lightning 1.0b2

Collector's Note My currently installed theme, good integration with Oxygen theme

Plastikthunder Crystal SVG by Víctor Fernández

Plastik style from KDE with Crystal SVG icons for...