YouTube High Definition is a powerful tool that will let you automatically play all YouTube videos in HD (High Definition), turn off annotations, change video player size, auto stop videos, auto mute videos, control embedded videos and much more.
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.
YouTube Flash Video Player is a powerful tool that will let you choose Flash video player as default YouTube video player.
Protects you against tracking through "free", centralized, content delivery. It prevents a lot of requests from reaching networks like Google Hosted Libraries, and serves local files to keep sites from breaking. Complements regular content blockers.
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!
Add-ons Manager Context Menu Requires Restart
Add more items to Add-ons Manager context menu.
'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!
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).
Open With Photoshop is a new companion for web and graphic designers to open up any web image with Adobe Photoshop via a single and quick mouse click.
Reader is the ultimate Reader tool for Firefox.
The Add-ons Manager slims down!
This add-on reduces the height of entries in the Add-on Manager, so you can display more of them at a time.
Save images and pages to your Pinterest account quickly and easily with Save Button for Pinterest.
Adds a new page that shows add-on memory usage
Restores the default image style used for top-level images in previous versions of Firefox.
Webmaster SAPE Requires Restart
Toolbar contains a set of functions, which expands the abilities of webmasters and optimizers, when working in the interface of SAPE exchange.
Go Parent Folder Requires Restart
Add "Go Parent Folder" menu to context menu in The Library list view and Search result in Bookmarks Sidebar.
Adds private tabs.
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.
Show My Password Requires Restart
You are annoyed because your password fields are always scrambled though nobody else but you can see the screen? This most advanced unscrambling addon shows your passwords in readable letters, while being fully customizable to fit your needs.
HTitle (discontinued) Requires Restart
Hide title bar if window is maximized.
[!] This add-on has been discontinued.
This extension created only for GNOME 3. It can create problems with another DE. However, you can use HTitle at your own risk (need enable "legacy" mode on settings).