Recently Updated Extensions
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.
Finally, an efficient blocker. Easy on CPU and memory.
'Classic Toolbar Buttons' add-on restores old toolbar button ui (known from Fx 4-7s small view, Fx 4-12s large view & Tb 5-14) for current Firefox, Thunderbird and Seamonkey versions.
Beta builds on versions page!
Saved Password Editor Requires Restart
Adds the ability to create and edit entries in the password manager.
Theme Font & Size Changer lets you change the global font size and font family used for the user interface in Firefox. Design your browser with your favorite font.
Google Keep for Thunderbird
UnMHT allows you to view MHT (MHTML) web archive format files, and save complete web pages, including text and graphics, into a single MHT file in Firefox/SeaMonkey.
QuickFolders (Tabbed Folders) Requires Restart
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!
Ad Blocker lets you block all ads, tracking & malware from the web world. It is an effective solution to browse the web without offensive and annoying ads you hate to see.
Adblock Plus Featured
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).
Before Tabs Toolbar Requires Restart
Adds a toolbar before the tabs.
DKIM Verifier Requires Restart
Verifies the DKIM-Signature of an e-mail.
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).
KeeFox Requires Restart
Simple and secure password management. Login automatically, never forget another password, stay in control of your passwords and improve their security. Powered by the world-renowned KeePass Password Safe.
Keep your menus in check by filtering out items you never use.
CryptoData Requires Restart
Easily and quickly to encrypt / decrypt:
Private messages via e-mail, blogs, social networks, forums, websites, images, etc
Support: Firefox, Thunderbird and SeaMonkey
Configures B-Trust security devices, imports B-Trust certification chain.
A powerful ad blocker that blocks ALL ads but ads from publishers who shares revenues with targets YOU choose.
Enigmail Requires Restart Featured
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.
Opacus SugarCRM 6.2+ Thunderbird Integration Pro Requires Restart
SugarCRM 6.2.0-7.6.x/SuiteCRM 7.x Integration for Thunderbird
Enables archiving of emails into SugarCRM and SuiteCRM from Thunderbird. Requires a purchased license key (you can request a trial from within the extension).