| FullScreen+ | | - | | |
| Full Screen Plus | | - | | |
| FoxyTab | | - | | |
| FoxTab | | - | | |
| FoxLocation | | - | | |
| FoxE9 | | - | | |
| FoxClocks | | - | | |
| Force Inverter - Text Inverter | | - | | |
| Foobar Controls | | - | | |
| Foobar | | - | | |
| Follower Tab for Firefox | | - | | |
| Focus Popup | | - | | |
| Focus Mode | | - | | |
| Focus Last Tab | | - | | |
| Focus Last Selected Tab | | - | | |
| Floaty Scrollbar | | - | | |
| Float Toolbars in Full Screen | | - | | |
| Flickr NewTab | | - | | |
| FlexBar | | - | | |
| FlagTab | | - | | |
| FishEyeTabs | | - | | |
| Firefoxボタンもしいたけに見えて困る | | - | | |
| Firefox Color | | - | | |
| Firefox Button Classic Menu | | - | | |
| FireTitle | | - | | |
| FireSearchBar | | - | | |
| FireFTP button | | - | | |
| Findbar autohide | | - | | |
| Findbar Favorites | | - | | |
| Findbar Basics | | - | | |
| FindBar Tweak | | - | | |
| Find Toolbar Tweaks | | - | | |
| Find To Center | | - | | |
| Find In Numbers | | - | | |
| Find Buttons | | - | | |
| Find Button | | - | | |
| Find All | | - | | |
| File and Folder Shortcuts | | - | | |
| FaviconizeTab | | - | | |
| Favicon Tabs | | - | | |
| Favicon Restorer | | - | | |
| FavTab | | - | | |
| FavIconInLocationBar | | - | | |
| Faster tab browsing | | - | | |
| Fast and Awesome | | - | | |
| Fast Tab Switcher | | - | | |
| Fast Navigation | | - | | |
| Fast Close Tabs | | - | | |
| Fantastic Bar | | - | | |
| FabTabs | | - | | |