Old-style smilies Requires Restart

Reverts the smilies in Thunderbird to those of version 2.

Flat Folder Tree Requires Restart

Selectively breakout or promote sub-folders under an intermediate folder in the folder tree. Use with IMAP servers where some folders remain collapsed under special namespace like [Gmail] or the INBOX itself.

Korean spellchecker

Korean (ko-KR) spellchecker

No More Install Delay

UPDATE: XPI delay has been removed in Firefox 40!

Disable the install delay in Firefox. New 2.0 version now includes GreaseMonkey scripts!

Unlike similar addons, this works on Firefox 4 and beyond.

Slovak spell checking dictionary

Slovak spell checking dictionary for Mozilla applications (based on the "open-source" dictionaries by Zdenko Podobný).

TamilVisai (TamilKey) Requires Restart

A utility for typing in Tamil language. It will be ideal for Tamil bloggers...

Restart application Requires Restart

Restart the application with one click (or Ctrl Shift Z)

Sender Name Requires Restart

DragToCompose Requires Restart

Enables dragging a file to Thunderbird for composing a new message without opening composer window first.

Show Password On Input Requires Restart

Gives an option to show the master password on input

Urdu Dictionary

This dictionary is based on the urdu word list provided at www.crulp.org and the word list compiled by our friends at http://www.urduweb.org/mehfil/

Free/Busy Requires Restart

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.

ThunderTabs Requires Restart

This add-on is a button on your toolbar that lets you open web apps as Tabs in Thunderbird. Use it to load Google Mail, Google Wave, Google Voice, and other "inboxes" (or any url) as tabs within Thunderbird, making it your communications hub.

English-Russian dictionary

Spelling of English and Russian words

FromToGMAP Requires Restart

Calculation of the distance and delay between reference address and highlighted address with the Google Map engine. Right click with mouse, select 'Distance with FromToGMAP' and the calculation of distance and delay appear in a popup

Search IP Requires Restart

This plugin adds three links to Firefox's context menu that lookup the selected IP address at Project Honey Pot, Utrace, spamhaus, senderbase,...

Srpski

Spell check dictionary for Serbian (Cyrillic and Latin)

AddressBookTab Requires Restart

It adds a button that can be put in toolbars and that open the addressbook in a new tab

JavaScript Object Examiner Requires Restart

Display JavaScript object methods and properties for any available scope.

tasks & mails Requires Restart

Tasks and emails management in a Thunderbird extension. tasks are stored in emails folder and it's possible to link an email to a task.
See all in one, emails and tasks (no more pain to synchronize a task manager).