Add-ons

DownThemAll! by Nils Maier, Federico Parodi, others

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

Collector's Note A great plugin if you want to maximize your speed or grab multiple items off a page.

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.

Collector's Note A great addition to Adblock Plus to allow you to get rid of content that might be tricky to block through the main add-on

Toolbar Buttons by Button Guy

Adds toolbar buttons to the customize toolbar window in several programs including Firefox, Thunderbird and SeaMonkey. Some of the buttons make commonly preformed actions quicker, others add new functionality.

Collector's Note Adds a bunch of useful buttons to the customize menu for your toolbars

Forecastfox Weather by Ensolis

Get international weather forecasts from AccuWeather.com and display them in any toolbar or statusbar with this highly customizable and unobtrusive extension.

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.

Collector's Note This extension lets you load the next page of a site onto the first page. I don't know how I ever lived without it.

CustomizeGoogle by CustomizeGoogle

CustomizeGoogle enhances Google by adding information and removing unwanted information.

Collector's Note If you use google, you should use this add-on as well. It allows you to block ads and click tracking as well as make search preferences stick without needing to maintain your google cookie.

MR Tech Toolkit by mrtech

(Formerly Local Install) The primary goal of this extension is to provide the tools needed to install and manage extensions and themes locally and tons of other features.

Note: With Toolkit 6.0 Auto Archiving is fully working in Firefox 2.0 and temp...

Collector's Note A multipurpose add-on useful for developers and non-developers alike.

Update Notifier by Todd Long

Note from Mozilla: This add-on has been discontinued. Try Add-on Update Checker instead.

Notifies you when updates are available for your extensions and themes.

Collector's Note More efficient at monitoring updates than the built-in checker.

Custom Buttons² by SCClockDr, nicholasalipaz, others

The Custom Buttons² Firefox extension provides the code base support necessary to create, maintain, import, and export custom toolbar buttons. The buttons can perform just about any task, with a large number of buttons already available on the exte...

Collector's Note Has a little bit of a learning curve but this extension lets you create custom buttons for firefox using javascript to make them do just about anything you want. The extension website features tons of user-made buttons which can be installed easily or customized. Theres also detailed documentation and a large community to provide help.