Appearance and Customization
CustomizeMyBird add-on offers ui tweaks to improve Thunderbirds appearance (squared tabs, custom tab height, alternative Add-on Manager appearance, compact main toolbars and more).
In the DOM Inspector,quickly navigate to the any elements
G-Hub Lite Requires Restart
Add Google Tabs to Thunderbird! Services supported: Voice, Calendar, Drive, Docs, Sheets, Slides, Hangouts, Plus, Photos, Contacts, News, Maps, & many more. Need Google Apps? Check out G-Hub Pro: http://www.schiffner.com/index.php/software/g-hub-pro
OutlookAlike BETA Requires Restart
Makes Thunderbird looking like Outlook.
Send YouTube video links to an external player, downloader, etc,
Functionality for multiple screens and windows. Easily open links in other windows or on other screens, move or merge tabs, and move or merge entire windows. With graphical controls for grid positioning.
Enable the View | Message Body As | All Body Parts message display mode.
Open about:config to change hidden settings that cannot be edited from the Options window. All Mozilla based programs have settings that can not be changed in the options window.
Send Later Button Requires Restart
A simple button to invoke the (already existing) send later functions.
A button to be able to open the profile folder, along with two buttons to create profiles, and also switch the current profile.
Extra Format Buttons Requires Restart
Adds a font size (in pixels), strikethough, subscript and superscript buttons to Thunderbird's Compose Window.
Adds icons to buttons and/or menus.
Set a minimum text size for all web content. Use the toolbar button to switch it on and off. NEW: Three preset sizes. NEW: Use mouse scroll on the toolbar button.
Keep your menus in check by filtering out items you never use.
Colorize entire web pages. Configure themes using sliders and drag-and-drop. Set domain preferences for automatic coloration.
Image viewer with smooth dynamic zoom, pan and rotate. View slide shows of images or files and capture page elements and tab content. Apply image filters. Save images in various formats.
Show all the menus in a single menu button that can be placed anywhere. Also contains replacement buttons for the default menus.
Stylish-Custom Requires Restart
custom additions to Stylish extension
Checkbox Column Requires Restart
Adds a custom column to Thunderbird's messages list (thread tree), making it easier to select multiple messages on devices with a touchscreen display.