Add-ons

FlashGot Mass Downloader by Giorgio Maone

Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.

Auto Resize Image by TrVTrV

Resizer for inline and attachment images (JPEG, PNG, BMP and GIF image formats).
All platforms are supported (Windows, Linux and Macintosh).

User Agent Switcher by chrispederick

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

Quicktext by John Bieling

Quicktext is an extension for Thunderbird that lets you create templates that can be easily inserted into your own emails.

Diccionario español México by eduardo_moreno

Diccionario para México.

Duplicate Contact Manager by Marian Steinbach, Copelnug

Facilitates handling of duplicates in your address book(s). Allow to search and remove similar contacts.

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!

Custom Address Sidebar by shimamu

Allow you to help address sidebar more useful.

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...

Sender Name by Takahiro Shinagawa

Restart application by Julien Fray

Restart the application with one click (or Ctrl Shift Z)

Select Address Book Text by craigm

Copy and paste a name, phone number, address or other text from your Thunderbird address book quickly, with just a single menu click.

Fit Images by V@no

Fit large images to window when viewing a message.
Control how you want to fit images: by width, height or both.