Thunderbird Extension

Notify on This Folder Not That Folder: A Thunderbird Extension allowing you to choose which accounts and folders to get notifications for. Also allows setting different sounds for each account.

A Thunderbird Extension/ Add-on which automatically sorts all incoming Mails from GitLab.

This Thunderbird (68+) Add On makes it easy to send large attachments: It uploads the files to Strato's Hidrive service and inserts download links into the message