Most Popular Extensions
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).
Lightning Requires Restart
Organize your schedule and life's important events in a calendar that's fully integrated with your Thunderbird email. Manage multiple calendars, create your daily to do list, invite friends to events, and subscribe to public calendars.
FlashGot Mass Downloader Requires Restart
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.
ImportExportTools Requires Restart
Adds some tools to import and export folders and messages
Stylish Requires Restart
Restyle the web with Stylish, a user styles manager. Stylish lets you easily install themes and skins for Google, Facebook, YouTube, Tumblr, and many, many other sites. You can even customize Firefox and other programs themselves.
Encrypt the web! HTTPS Everywhere is a Firefox extension to protect your communications by enabling HTTPS encryption automatically on sites that are known to support it, even when you type URLs or follow links that omit the https: prefix.
Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.
Provider for Google Calendar Requires Restart
Allows bidirectional access to Google Calendar
S3.Google Translator Requires Restart
S3.Google Translator adds the power of Google Translate’s automatic translations to your browser!
It supports translation of selected text, entered phrase or whole webpage between any of 80+ languages.
New Feature: Language learning!
Full Web Page Screenshots (♥♥♥♥♥) Requires Restart
FireShot makes full web page screenshots. Demo: http://bit.ly/RlBQMV
Screenshots can be quickly captured and:
― Saved as Image or PDF
― Sent to clipboard
― Annotated *
― Uploaded *
― E-Mailed *
* OS Windows only
Quick Locale Switcher Requires Restart
Allows you to quickly switch to a different language (User Interface, Spell Checker Dictionary and Website content) in your Mozilla application.
LookOut Requires Restart
LookOut is a plugin which allows Thunderbird to interface with Microsoft's mail tools by decoding metadata and attachments encapsulated/embedded in a TNEF encoded attachment (aka winmail.dat).
FoxyProxy Standard Requires Restart
FoxyProxy is an advanced proxy management tool that completely replaces Firefox's limited proxying capabilities. For a simpler tool and less advanced configuration options, please use FoxyProxy Basic.
This add-on allows you to export your saved passwords and disabled login hosts using XML or CSV files that can be imported later.
Note: This add-on won't work in Firefox 57. It may eventually if the APIs to access passwords are implemented.
If you are the kind of person who likes to have total control over every aspect of your downloads, "Download Status Bar" is the add-on you are looking for.
Personas (now known as lightweight themes) are free, easy-to-install "skins" for Firefox. Personas Plus extends that built-in functionality to give you even more control and easier access to new, popular, and your own favorite themes.
Manually sort folders Requires Restart
This extension allows you to manually sort (order) your folders in the folder pane of Thunderbird or automatically sort them, but in a better way. This extension also allows you to re-order accounts in the folder pane.
Menu Wizard Requires Restart
Customize menus : Helps removing, moving and renaming menus and menu items
Colorize important menu for ease of use! (use Style (CSS))
Change or disable any of used keyboard shortcuts
Support: Firefox, Thunderbird and SeaMonkey
SQLite Manager Requires Restart
Manage any SQLite database on your computer.
Enigmail Requires Restart Featured
OpenPGP message encryption and authentication for Thunderbird and SeaMonkey.