Add-ons

Enigmail by Patrick Brunschwig

Helper tool to migrate your keys and important settings from Enigmail to Thunderbird 78.

Mail Redirect by Onno Ekker, Pawel Krzesniak

Allow to redirect (a.k.a. "remail") mail messages to other recipients.

Collector's Note 0.7.4 for Thunderbird 3.x http://mailredirect.mozdev.org/

Thunderbird Conversations by Jonathan Protzenko, Standard8

This addon provides a conversation view for Thunderbird, grouping messages together and allowing you to reply "inline" thus providing a more efficient workflow.

Signature Switch by Achim Seufert

Switch the signature on/off or choose a new one from your predefined set.

CompactHeader by jmozmoz

Add symbol in header plane to switch between compact and expanded view. Work only for Thunderbird 68.0 and older. Currently, there are no plans to update this for newer versions.

Stationery by Arivald

Extension to mimic Outlook Express Stationery.
Allow you to use HTML files as templates for mail. Also allow custom template in replies or forwarded mail!

LightningButton by rsjtdrjgfuzkfg

Toolbar-Buttons for Lightning; advances the feature to get rid of the tabbar.

XNote++ by opto

Persistent sticky notes associated to emails. You can fulltext search with constraints/email them/print/bookmark/copy to clipboard.

If you have a large screen, you can even display the notes outside of TB's main window, so it won't hide anything.

Google Calendar Tab by Bryan Clark

Adds the Google Calendar web interface as a new tab directly into Thunderbird. Creating and viewing events works just as it would in a browser like Firefox

Xpunge by Theodore Tegos

Empties the Trash and Junk folders, and compacts folders in multiple Thunderbird accounts.

ThunderBrowse by GS! Networks

Did your friend send you a cool link? Want to read the rest of that interesting article? Don't want to open up your web browser just to view it? You don't have to! Just view it in Thunderbird with ThunderBrowse!

Contacts Sidebar by Jeroen Peters

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.

Collector's Note Thunderbird 3 support 0.8pre http://jpeters.no-ip.com/extensions/?page=tb_cs

Hide Menubar by yuoo2k

Supports to hide Menu Bar automatically, you can press the ALT key to show it temporarily.

New Tab Button by H.Ogi

It provide you the following functionalities:
* Open a selected message in a tab by a toolbar button
* Open a message in a tab by double-clicking its header view (disabled by default)
* Hide Lightning's Today Pane on opening a tab

Slideshow by Leszek Życzkowski, pastisman

Displays a slideshow of picture attachments. When email has attached pictures, it displays "View as Slideshow" button next to the attachment. Button click pops a slideshow window with all the images, allowing you to zoom in/out, save...