ActiveState Komodo
- Professional IDE for open source languages, offering support for Perl, PHP, Python, Tcl, and XSLT.
- http://www.activestate.com/products/komodo_ide/

PrefBar
- The Preferences Toolbar for SeaMonkey, Mozilla, and Firefox allows for quick changes of frequently accessed preferences.
- http://prefbar.mozdev.org/

Mozilla XUL Runtime Project
- Project aiming to create a XUL runtime that requires no browser.
- http://developer.mozilla.org/en/docs/XULRunner

XUL Applications
- XUL applications/utilities for Mozilla (and Netscape 7). They are based on the specification of Mozilla Nightly Trunk. Works on Netscape 7.0, Mozilla 1.0, Phoenix 0.5, or later.
- http://piro.sakura.ne.jp/xul/xul.html.en

Link Toolbar
- An add-on toolbar for mozilla that implements parsing of the <link> element for HTML
- http://segment7.net/projects/mozilla/linktoolbar/

ZULU
- A layout engine for producing rich cross-platform user interfaces, using XUL standard and Flash MX technology.
- http://zulu.netspedition.com/zulu/main/overview.shtml

Mozilla Amazon Browser (MAB)
- A tool for searching and browsing the Amazon database.
- http://mab.mozdev.org

Venkman Project Page
- JavaScript debugger extension for Mozilla and Netscape browsers.
- http://www.mozilla.org/projects/venkman/

ZopeStudio
- A management and development environment for the Zope application server.
- http://www.zope.org/Products/ZopeStudio/