CompactHeader Requires Restart Featured
Add symbol in header plane to switch between compact and expanded view. New beta versions for the current beta of Thunderbird 68.0 can be found at https://github.com/jmozmoz/compactheader/
Mail Redirect Featured
Allow to redirect (a.k.a. "remail") mail messages to other recipients.
CardBook Requires Restart Featured
A new Thunderbird address book based on the CardDAV and vCard standards.
Mail Merge Requires Restart Featured
Create and Save or Send Multiple Individual and Personalized Messages from a Draft
Enigmail Requires Restart Featured
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.