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.
Allows bidirectional access to Google Calendar
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).
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
Switch the signature on/off or choose a new one from your predefined set...
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 38+ only (see below for details).
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.
Contact Tabs enhances Thunderbird to give you quick access to all your contacts directly from Thunderbird's main window: Use the powerful search field to find your contacts and open them in a new tab for viewing and editing.
This extension is for those TB3 users who want the multiple-columns view that TB2 allowed
True "Send Later" functionality to schedule the time for sending an email.
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.
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
Search and remove messages which are the same as other messages in your mail folders (referred to as duplicates or dupes).
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.