Flexible Sidebar allows to change sidebar width by dragging the handles.
Telegram Web Messenger brings Telegram right into your Firefox Sidebar.
SeaMonkey Vertical Tab Bar Requires Restart
Tab bar on the side of the window for SeaMonkey.
A full featured color selector tool, to work with colors, and easily find the colors you want.
Google Hangouts Web Messenger brings Google Hangouts right into your browser to chat with your friends.
YouTube Video Player Pop Out lets you pop out YouTube videos so that you can watch YouTube videos while you surf.
jsbtn Requires Restart
JS on/off status bar button
Tategaki Requires Restart
Tategaki allows vertical writing-mode on mail compose window.
This extension makes browsing for extensions easier at addons.mozilla.org. It fixes incorrect information about some extensions being not available for SeaMonkey and adds links to the Add-on Converter where needed.
Open With Internet Explorer sends pages from Mozilla Firefox to Internet Explorer.
Restart Application Button lets you restart your Firefox and SeaMonkey application by a quick toolbar button click.
The "Responsible Blocker" arrives to save the Internet, this extension blocks all those annoying ads, but allows only small and acceptable ads, so the websites you like can continue online.
The "Responsible Blocker" arrives to save the Internet
Add-on for Firefox and Thunderbird. Replaces built-in notifications with the OS native notifications. It supports most Linux Desktop Environments, Windows 8.1 & 10.
GNOMErunner Options Requires Restart
Allows to customize GNOMErunner theme
Stylish-Custom Requires Restart
custom additions to Stylish extension
Open With Vivaldi Browser sends pages from Mozilla Firefox to Vivaldi browser.
Speed Dial & Start Page with flexible layout for fast access to sites via visual bookmarks
Reopens the last closed tab.
A button to be able to open the profile folder, along with two buttons to create profiles, and also switch the current profile.