Add-on Update Checker

Adds Tools menu item to check Add-ons for updates. Includes toolbar icon.

Rated 4 out of 5 stars (51)
14,643 users

µBlock No Restart

Finally, an efficient blocker. Easy on CPU and memory.

Rated 4 out of 5 stars (212)
222,276 users


Quitomzilla helps you quit smoking while you surf the web or wait for new emails, showing the cigarettes, money and time you have saved since you quit...

Rated 5 out of 5 stars (18)
512 users

PONG! Multiplayer

Play a game of PONG! while you are waiting.

Rated 5 out of 5 stars (7)
95 users

Mouse Gestures Suite

Mouse gestures for SeaMonkey & Firefox: navigate & execute commands using mouse gestures (with single mouse button) and rocker gestures (by pressing 2 mouse buttons). Also: scroll wheel navigation, page scrolling, tab scrolling.

Rated 4 out of 5 stars (22)
7,809 users

TabSubmit No Restart

Lets the user direct the submission of a form to a new tab or window. [Bug #17754]

Rated 5 out of 5 stars (14)
895 users

BOINC Stats 2

Displays your Total and Recent Average Credits for BOINC distributed computing projects in the status bar.

Rated 5 out of 5 stars (4)
42 users

Extension List Dumper 2

This extension adds a button ("Dump list") to the Add-ons window. When this button is pressed, a new window is opened with the list of installed extensions, themes or plugins...

Rated 5 out of 5 stars (16)
330 users


Standalone calendar UI for Lightning

Rated 5 out of 5 stars (10)
4,579 users

Copy Sent to Current

Allows to place a copy of sent messages (aka FCC) into the currently active folder or any other folder you choose, when you create the message. Usually the copies are placed into the 'Sent' folder. For replies, you may also move the original message.

Rated 4 out of 5 stars (61)
3,529 users


Lists installed add-ons (extensions, themes, plugins). Compatible version linked from the Developer comments section at the bottom of the addon's page.

Rated 4 out of 5 stars (30)
845 users

Tab notifier

Enables desktop notifications like in Chrome (e.g. Gmail, imo.im) and, if the site doesn't support them, it can notify new messages or updates detecting changes of the title (e.g. Hotmail, Yahoo, Facebook, Twitter). Even if the browser is minimized!

Rated 4 out of 5 stars (40)
6,093 users

FoxClocks No Restart

FoxClocks shows times around the world - or just your local time - at the bottom of your browser. It deals with daylight saving time so you don't have to.

Rated 4 out of 5 stars (311)
67,103 users


A clean, easy to use and highly extensible Internet Relay Chat (IRC) client.

Rated 4 out of 5 stars (126)
150,137 users

Snap Links Plus

Select a number of links with a rectangle and open them all in new tabs in the same or a new window(s), download them or copy them to the clipboard. You can also lasso checkboxes to quickly check or uncheck them.

Rated 4 out of 5 stars (97)
23,103 users


Synchronizes contacts & groups between Thunderbird or SeaMonkey and Google Contacts. Imports Facebook friends, contacts you follow on Twitter, and more.

Rated 4 out of 5 stars (202)
65,909 users

Year view

Year view for calendar.

Rated 4 out of 5 stars (44)
4,363 users

WebODF No Restart

Viewer for OpenDocument Format office files. It can display documents saved from LibreOffice, OpenOffice, Calligra, Abiword, Microsoft Word, Excel, PowerPoint. The documents should be saved in the OpenDocument Format.

Rated 5 out of 5 stars (6)
2,113 users

Mail Redirect

Allow to redirect (a.k.a. "remail") mail messages to other recipients.

Rated 4 out of 5 stars (124)
33,342 users

Copy As Plain Text

Removes formatting from copied text.

Rated 4 out of 5 stars (56)
26,560 users