Most Popular Extensions
Allows bidirectional access to Google Calendar
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.
Adds tools to import/export messages and folders (NextGen)
NEW 78/68 Compatible version !
See Changes below
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).
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).
TbSync is a central user interface to manage cloud accounts and synchronize their contact, task and calendar information with Thunderbird.
OpenPGP message encryption and authentication for Thunderbird.
A new Thunderbird address book based on the CardDAV and vCard standards.
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
True "Send Later" functionality to schedule the time for sending an email.
This extension adds support for CalDAV & CardDAV accounts to the Thunderbird Sync manager "TbSync". Including iCloud, ownCloud, Nextcloud, Radicale and many more.
Switch the signature on/off or choose a new one from your predefined set.
Allows you to use your Exchange email accounts that use Outlook Web Access (OWA) with Thunderbird
ImportExportTools Requires Restart
Adds some tools to import and export folders and messages
Confirm E-mail address before sending mail
Thunderbird Conversations Featured
This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.
Add sync support for Exchange ActiveSync (EAS v2.5 & v14.0) accounts to TbSync
Adds the Google Calendar web interface in a new Thunderbird tab. Creating and viewing events works like in a browser (Firefox, Chrome, ...)
Uploads your large attachments to your Dropbox instead of sending them by email. This uses Thunderbird's FileLink feature.