My "I don't know how I lived without this and that", essentials, plus a few more to simplify and complete my thunderbird. Peace. Kir_B
Blocks annoying video ads on YouTube, Facebook ads, banners and much more.
Adblock Plus blocks all annoying ads, and supports websites by not blocking unobtrusive ads by default (configurable).
Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.
Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.
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!
The "Swiss army knife" of folders. Turn your favorites into tabs - open folders and subfolders, move mails without scrolling around or searching. powerful + easy.
See new mail at a glance after automatic filtering - supports quickFilters addon!
Add a compact menu button to the navigation toolbar, and hide the menu bar.
Transforms typed or static text to L337, ROT13, BASE64, HEX, URL, BIN, DES, AES, Morse code, DVORAK keyboard layout and to lower/to upper case functionality, Leet Font...
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.
Toggle word wrapping and PRE element wrapping in the message composition and HTML display windows, respectively.
Auto Zip Attachments allows you to easily compress (zip) attachments.