Quote Colors allows you to select text and background colors of different quote levels which are applied when reading or printing mail/news messages. Additionally, you can choose between graphical and traditional plain text quoting display mode.
Compressor for attachment files. All platforms are supported (Windows, Linux and Macintosh).
Add arrow buttons for rotating among folder views, and switch to "All Folders" view when hovering over the folder pane during drag & drop.
Allows to modify the header and the source of messages
Tasks and emails management in a Thunderbird extension. tasks are stored in emails folder and it's possible to link an email to a task.
See all in one, emails and tasks (no more pain to synchronize a task manager).
Adds Text Color Buttons in Compose Toolbar and More: Pixel FontSize, Strikethough, Sub & Superscript, Lower & UpperCase. Also provide Tools: Insert iframe, Launch MathType, Maths & Greek Symbols, Load Template Variables and Duplicate Compose Window.
Makes search results sort by "date" instead of "relevance" by default.
This add-on allows you run your message filters automatically on outgoing messages after sending. In other words, it's a outgoing filter for thunderbird and seamonkey.
Provides keyboard shortcuts for filing messages into nine configurable "favorite" folders using user-defined keys. Also provides a simple filter system with a keyboard shortcut to file the currently selected message(s) into the correct folder.
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...
This add-on provides features to avoid sending emails to wrong addresses. Key features are a confirmation window of recipient's addresses upon sending, name and affiliation look up at mail composition and main windows, and safe auto completion.
Allow you to add a Address Move Button to mail compose window.
Maximize message pane by collapsing the thread pane. You can read a message in larger area without opening a new message window...