Add-ons specific to Firefox' Linux build functionality.
Add-ons that have obscure, limited or unusual purpose. Mostly web development type add-ons.
Add-ons that help protect your privacy & security while browsing
Greasemonkey / Scriptish, Stylish, and other similar Add-ons that let you change the way a website looks, plus addons that enhance or extend the functionality of those primary Add-ons.
Add-ons that enhance particular online games or games/sports websites; pull games; or pull sports related content
Temporary junk drawer. Add-ons I'm trying out or have tried out. Please note that add-ons will be move in and OUT of this collection.
Add-ons that I've found useful. Not essential, merely useful at times.
Haven't used but looks interesting. Add-ons I think I might try out someday.