| GG.GG URL Shortener | | - | | |
| GBookmarks (Google Bookmarks for Firefox) | | - | | |
| Furaffinity Submissions extension | | - | | |
| Furaffinity Preview | | - | | |
| FurAffinity Filter | | - | | |
| FurAffinity Extender | | - | | |
| Fullsize Image viewer for GooglePlus | | - | | |
| Frompo | | - | | |
| FreeDictionaryPopPanel | | - | | |
| FoxyWebSearch | | - | | |
| FoxyTracks | | - | | |
| FoxAge2ch | | - | | |
| Fotofox | | - | | |
| Forvo it! | | - | | |
| Forecastfox (fix version) | | - | | |
| Forecastfox | | - | | |
| Forecast Plus | | - | | |
| FootieFox | | - | | |
| Fluidinfo | | - | | |
| Fluid twitter layout | | - | | |
| Floating Panel for YouTube | | - | | |
| Flickr Gallery Plus! | | - | | |
| Firefox Sync | | - | | |
| Firefox Share (alpha) | | - | | |
| Firefox Search Sidebar | | - | | |
| Fireflix | | - | | |
| FireTube | | - | | |
| FireStatus | | - | | |
| Fire.fm | | - | | |
| Fire Shabelet | | - | | |
| Film Info and Reviews | | - | | |
| Fess Google Bookmark Extension | | - | | |
| Feedly Notifier Plus | | - | | |
| Feedly Notifier | | - | | |
| Feed Filter | | - | | |
| FastestFox | | - | | |
| FastBrowz | | - | | |
| Fast Translation | | - | | |
| Fast Translate | | - | | |
| Fast Search by Surf Canyon | | - | | |
| Fast Image Search | | - | | |
| Fast Image Research | | - | | |
| F1 by Mozilla Labs | | - | | |
| Exposure New Tab | | - | | |
| Exch | | - | | |
| Evernote Web Clipper | | - | | |
| Enjoy Browser | | - | | |
| Email Yourself! | | - | | |
| Email This! Bookmarklet Extension | | - | | |
| Eiga.com Check-in Alert Notifier | | - | | |