Extensions by Weekly Downloads
ImportExportTools Requires Restart
Adds some tools to import and export folders and messages
Allows bidirectional access to Google Calendar
Helper tool to migrate your keys and important settings from Enigmail to Thunderbird 78.
FlashGot Mass Downloader Requires Restart
Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.
Auto Resize Image Requires Restart
Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).
A new Thunderbird address book based on the CardDAV and vCard standards.
This extension allows you to manually sort (order) your folders in the folder pane of Thunderbird or automatically sort them, but in a better way. This extension also allows you to re-order accounts in the folder pane.
Saved Password Editor Requires Restart
Adds the ability to create and edit entries in the password manager.
gContactSync Requires Restart
Synchronizes contacts & groups between Thunderbird and Google Contacts.
Thunderbird email accounts connecting to Microsoft Exchange Web Services.
Fixed version (no 90 day timer till silent failure) of the popular "Theme Font & Size Changer for Thunderbird" addon
SQLite Manager Requires Restart
Manage any SQLite database on your computer.
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
LookOut decodes winmail.dat (TNEF encoded) files that may come from a misconfigured Microsoft Exchange server or Outlook user allowing access to the original attachments
DKIM Verifier Featured
Verifies the DKIM-Signature of an e-mail.
True "Send Later" functionality to schedule the time for sending an email.
Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.
LookOut Requires Restart
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).
This add-on allows you to export your saved passwords and disabled login hosts using XML or CSV files that can be imported later.
Note: This add-on won't work in Firefox 57. It may eventually if the APIs to access passwords are implemented.
Search and remove messages which are the same as other messages in your mail folders (referred to as duplicates or dupes).