Netscape Link Pad
Link Pad is a sidebar that you can drop links onto to save for later without cluttering your bookmarks. Find a link to a YouTube video you want to watch, but do not have time now? Drop it into Link Pad, and save it for later.
OPML Support
OPML Support adds OPML import/export functionality to the Firefox Bookmarks manager. OPML is a file type that is widely used to distribute lists of RSS/newsfeeds.
Resizeable Textarea
A lot of forums and boards provide very small textareas for new postings. If you type a longer posting, you have to scroll up and down, to read what you have written and to proceed. This situation is annoying.
Restarter
Add 'restart' to file menu. In Firefox 2.0 there are situations where you want to restart (eg changing theme) but there is no restart button, so you don't get a saved session. This makes restart visible always.
Simple Green
This theme is a refreshingly clean, compact theme based off the Navigator theme. It is a combination theme for both Mozilla Firefox and its companion mailnews client, Thunderbird.
The original author is Andy Fraley.
Splash!
Adds a splash screen to most Mozilla and Mozilla Based products. Supports sound, opacity, CSS customization, custom images, and much more.
Split Browser
This splits the content area of the browser window as you like. It will help you in various cases. For example, to compare multiple webpages, to show a calendar always, and so on.
Tab History
New tabs retain the session history of the originating tab. Links opened in a new tab won't have a blank history, but one that is populated from the "parent"...
Tab Mix Plus
Tab Mix Plus enhances Firefox's tab browsing capabilities. It includes such features as duplicating tabs, controlling tab focus, tab clicking options, undo closed tabs and windows, plus much more.
URL Fixer
URL Fixer corrects typos in URLs that you enter in the address bar. For example, if you type google.con, it will correct it to google.com (asking first, if you enable confirmation)...
Add-ons Sandbox
Some of these add-ons are still available only in the Mozilla Add-ons sandbox; read this for more information about the sandbox.
Propeller Add-ons
The following social news features were standard components of early betas of Netscape Navigator 9.