| Unload Tab (927284) | | - | | |
| UnloadTab | | - | | |
| UnloadTabs | | - | | |
| Unpin All | | - | | |
| Unread Tab | | - | | |
| UnreadTabTracker | | - | | |
| Unsearched | | - | | |
| Url Bar Font Bigger | | - | | |
| Urlbar autocomplete hotkey | | - | | |
| UrlbarExt | | - | | |
| Useful New Tab Page | | - | | |
| VerTabs Deluxe | | - | | |
| Version in Toolbar | | - | | |
| Vertical Bookmarks Toolbar | | - | | |
| Vertical Tabs | | - | | |
| Vertical Tabs (Simplified) | | - | | |
| Vertical Tabs Reloaded | | - | | |
| Vertical Toolbar | | - | | |
| Very Simple Tab Locker | | - | | |
| View Image In New Tab | | - | | |
| View Page Source Button | | - | | |
| View Page Source in Tab | | - | | |
| View Sidebar | | - | | |
| VisitChecker | | - | | |
| Visual Tabs | | - | | |
| VivaldiFox | | - | | |
| WDT - toolbar button | | - | | |
| WebToolHub | | - | | |
| Webpage Sidebar | | - | | |
| What about | | - | | |
| Wheeltab | | - | | |
| WideSearchBar | | - | | |
| WikifyTabs | | - | | |
| Window Merger | | - | | |
| Window and Tab Limiter | | - | | |
| Work offline | | - | | |
| WorkspaceHopper | | - | | |
| Workspaces for Firefox | | - | | |
| Yant | | - | | |
| Yet Another Tab Counter | | - | | |
| about：NewTab | | - | | |
| akumar09071988 | | - | | |
| bookmarks history panel | | - | | |
| bookmarks-deiconizer | | - | | |
| browsingfox | | - | | |
| bug489729 (Disable detach and tear off tab) | | - | | |
| bug892485_PreventScrollOnHistory | | - | | |
| clear the search bar | | - | | |
| dM Tab-Counter | | - | | |
| deduplicate-tabs | | - | | |
