http://developer.mozilla.org/en/docs/Building_an_Extension -tut
http://kb.mozillazine.org/Getting_started_with_extension_development -tut
http://ted.mielczarek.org/code/mozilla/extensionwiz/ - Wizard generates an extension skeleton
Extensions add new functionality to Mozilla applications such as Firefox and Thunderbird. They can add anything from a toolbar button to a completely new feature. They allow the application to be customized to fit the personal needs of each user if they need additional features, while keeping […]

Manage any SQLite database on your computer.
Manage any SQLite database on your computer. An intuitive heirarchical tree showing database objects. Helpful dialogs to manage tables, indexes, views and triggers. You can browse and search the tables, as well as add, edit and delete the records. Facility to execute any sql query. A dropdown menu helps […]

Manage any SQLite database on your computer. An intuitive heirarchical tree showing database objects. Helpful dialogs to manage tables, indexes, views and triggers. You can browse and search the tables, as well as add, edit and delete the records. Facility to execute any sql query. A dropdown menu helps with the sql syntax thus making […]

FireShot is a Firefox extension that creates screenshots of web pages.
Unlike other extensions, this plugin provides a set of editing and annotation tools, which let users quickly modify captures and insert text and graphical annotations. Such functionality will be especially useful for web designers, testers and content reviewers.
It’s possible to choose whether entire web page […]

This extension allows you to use your Gmail Space (4.1 GB and growing) for file storage. It acts as an online drive, so you can upload files from your hard drive and access them from every Internet capable system. The interface will make your…
Long Description
This extension allows you to use your Gmail Space (4.1 GB […]

FoxyProxy is an advanced proxy management tool that completely replaces Firefox’s limited proxying capabilities. It offers more features than SwitchProxy, ProxyButton, QuickProxy, xyzproxy, ProxyTex, TorButton, etc.
Long Description
FoxyProxy is a Firefox extension which automatically switches an internet connection across one or more proxy servers based on URL patterns. Put simply, FoxyProxy automates the manual process of […]

FireFTP is a free, secure, cross-platform FTP client for Mozilla Firefox which provides easy and intuitive access to FTP servers.
Along with transferring your files quickly and efficiently, FireFTP also includes more advanced features such as: directory comparison, syncing directories while navigating, SSL encryption, search/filtering, integrity checks, remote editing, drag & drop, file hashing, and much […]

This is a great tool for web developers, since you can easily see how your web page displayed in IE with just one click and then switch back to Firefox.
https://addons.mozilla.org/en-US/firefox/addon/1419

Long Description
Allows you to customize the way a webpage displays using small bits of JavaScript.
Hundreds of scripts, for a wide variety of popular sites, are already available at http://userscripts.org.
You can write your own scripts, too. Check out http://wiki.greasespot.net/ to get started.
Works with:
* Firefox: 1.5 – 3.0b5
See All Versions
Homepage
http://www.greasespot.net/
Reviews
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The best security you can get in a web browser!
Allow JavaScript, Java and other executable content to run only from sites you trust.
Long Description
Winner of the “2006 PC World World Class Award”, this tool provides extra protection to your Firefox.
It allows JavaScript, Java and other executable content to run only from trusted domains of your […]

Automate Firefox. Record and replay repetitious work. If you love the Firefox web browser, but are tired of repetitive tasks like visiting the same sites every days, filling out forms, and remembering passwords, then iMacros for Firefox is the solution you’ve been dreaming of! ***Whatever you do with Firefox, iMacros can automate it.***
Long Description
iMacros was […]