1 146 057 gebruikers
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.
296 859 gebruikers
Allows bidirectional access to Google Calendar
157 792 gebruikers
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
192 583 gebruikers
LookOut is a plugin which allows Thunderbird to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).
77 903 gebruikers
This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.
The latest version is compatible with Thunderbird 31+ only (see below for details).
115 497 gebruikers
ReminderFox displays and manages lists of reminders and ToDo's. ReminderFox makes sure you remember all of your important dates via easy-to-use lists, alerts, and alarms, right in your browser without the need for a separate calendar program.
99 952 gebruikers
Help make Firefox better. The Add-on Compatibility Reporter enables you to report if the Firefox add-ons that you're using are working properly.
198 994 gebruikers
This extension is for those TB3 users who want the multiple-columns view that TB2 allowed
91 920 gebruikers
Switch the signature on/off or choose a new one from your predefined set...
51 848 gebruikers
True "Send Later" functionality to schedule the time for sending an email.
76 066 gebruikers
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
38 289 gebruikers
Displays the address books in a sidebar in Thunderbirds 3-pane-window and can be toggled with the F4 key or a toolbar button.
Visit my Contacts Sidebar site for recent versions and news.
65 722 gebruikers
Search and remove messages which are the same as other messages in your mail folders (referred to as duplicates or dupes).
164 717 gebruikers
Add symbol in header plane to switch between compact and expanded view. Options to switch between one or two lines compact view, which buttons should be displayed in header pane. Linkify RSS subject. Optionally darkens header if message has focus.