Дополнения

Send Later от Jonathan Kamens, Jonathan Perry-Houts

“Send Later” - планировщик времени отправки сообщений электронной почты.

Signature Switch от Achim Seufert

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

CompactHeader от 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 от Leszek Życzkowski

Копирует выделенный текст без форматирования.

MRC Compose от 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 от 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 от Michael J Gruber

Collapse and expand quotes.

Contributors: Stanimir Stamenkov, Dillinger

Return Receipt Toolbar Button от Leszek Życzkowski

Добавляет кнопку "Уведомление о прочтении" на панель инструментов окна составления сообщения.

Slideshow от Leszek Życzkowski, pastisman

Просмотр вложенных в письмо изображений
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 от 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 от WongKit