Add-ons

DownThemAll! by Nils Maier, Federico Parodi, others

The first and only download manager/accelerator built inside Firefox!

FlashGot Mass Downloader by Giorgio Maone

Download all the links, movies and audio clips of a page at the maximum speed with a single click, using the most popular, lightweight and reliable external download managers.

User Agent Switcher by chrispederick

The User Agent Switcher extension adds a menu and a toolbar button to switch the user agent of a browser.

FireFTP by Mime Čuvalo

FireFTP is a free, secure, cross-platform FTP/SFTP client for Waterfox which provides easy and intuitive access to FTP/SFTP servers.

Check out my new project, FireSSH!

Element Hiding Helper for Adblock Plus by Felix Dahlke

Fight the text ads! Element Hiding Helper is a companion extension for Adblock Plus meant to make creating element hiding rules easier.

Live HTTP Headers by Daniel Savard, Nikolas Co

View HTTP headers of a page and while browsing.

HttpFox by Martin Theimer

An HTTP analyzer addon for Firefox

AutoProxy by lovelywcm

Are you concerned about your privacy? Or, are you blocked from some websites by a firewall? And, are you arming yourself with a proxy? In that case, AutoProxy is designed for you! A tool to help you use your proxy automatically & efficiently.

Silvermel by ShareBird

A Creamy Silvery Experience

DOM Inspector by SeaMonkey Council

DOM Inspector is a tool that can be used to inspect and edit the live DOM of any web document or XUL application. The DOM can be navigated using a two-paned window displaying a variety of different views on the document and all nodes within.

WorldIP - Geo Add-on with Security Features by Alrond

Professional Geo Add-on with security features and advanced network tools. Anti-phishing. Protection against DNS spoofing and fake sites. All DNS records for domain. The real location of web server, country flag, extended information about datacenter

QuickDrag by Stevie Smith

Extends the function of the drag-and-drop mouse gesture so that it can be used to load URLs, do a web search of selected text on a page, or save an image on a page. The successor to Super DragAndGo.

AutoPager by Wind Li

AutoPager automatically loads next pages when you reach the end of a page. It works on a ton of sites,Google,Yahoo..
It works well with most other add-ons adblock plus, WOT and most of the greasemonkey scripts.
You can also try AutoPagerLite.

Google Reader New Style Minimalistic By DemianGod by DemianGod

Removes all the junk from New Google Reader and just gives you the search and collapsable subscriptions + favicons. By DemianGod

Also you can install the Script for GreaseMonkey.
Download from: http://userscripts.org/scripts/show/30242

sleek stuff by jwelton