| 3d-flip-tab-switch | | - | | |
| A Better Firefox Add-on Bar | | - | | |
| A Double Click to Close Tab | | - | | |
| AFx 8-O Nav Bar Buttons (48px) | | - | | |
| AFx 8-O Nav Bar Buttons (64px) | | - | | |
| ALL ROBOT | | - | | |
| Aaapptabs | | - | | |
| About support button | | - | | |
| Activate Left Tab On Close | | - | | |
| Active Tab Switcher | | - | | |
| Add Page Title To URL Bar | | - | | |
| Add URL to Window Title | | - | | |
| Add-on Toolbarbutton | | - | | |
| Addons in Urlbar | | - | | |
| AddressBarCleaner | | - | | |
| Advanced Locationbar | | - | | |
| Advanced Search | | - | | |
| Advanced Tab Navigation | | - | | |
| AdvancedClose | | - | | |
| Aero Window Title | | - | | |
| Aggregate Tabs to Main Window | | - | | |
| AlexFlipnote／Homepage | | - | | |
| All About Location Bar | | - | | |
| All Menus Button | | - | | |
| All Tabs Helper | | - | | |
| All Tabs Restorer | | - | | |
| All the Tools | | - | | |
| All-in-One Sidebar | | - | | |
| Alt New Tab | | - | | |
| Always Awesome Bar | | - | | |
| Always Right | | - | | |
| Any New Tab | | - | | |
| App Button Clear | | - | | |
| App Button Color | | - | | |
| App Button No Text | | - | | |
| App Button Remove | | - | | |
| App Tab Initializer | | - | | |
| AppTab Nav-B-Gone | | - | | |
| AppTabs Plus | | - | | |
| Append Domain | | - | | |
| Append New Tab | | - | | |
| Attack On The Clones | | - | | |
| Australis Minimalis | | - | | |
| Australis Slimmr | | - | | |
| Australis Small Icons | | - | | |
| Australis-like refresh in URL bar | | - | | |
| AustralisBookBar | | - | | |
| Auto Close Tab | | - | | |
| Auto Close Tabs | | - | | |
| Auto Complete | | - | | |
