Add-ons

Send Later by Jonathan Kamens, Jonathan Perry-Houts

True "Send Later" functionality to schedule the time for sending an email.

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.

Copy Plain Text 2 by Leszek Życzkowski

Copies text without formatting

MRC Compose by Michel Renon

Remplace la liste d'adresses par les champs standards (Pour, Copie à, Copie cachée à) avec l'autocomplétion.
Provides standards fields (TO, CC, BCC) with autocomplete to Thunderbird's compose pane.
For bug reports, please use support email.

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.

QuoteCollapse by Michael J Gruber

Collapse and expand quotes.

Contributors: Stanimir Stamenkov, Dillinger

Return Receipt Toolbar Button by Leszek Życzkowski

Allow you to add a Return Receipt button to mail compose window toolbar.

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...

AddressBookTab by pastisman

It adds a button that can be put in toolbars and that open the addressbook in a new tab

Light grey theme for Thunderbird by WongKit