Twist is an open-source Java add-on collection for the Standard Widget Toolkit (SWT) aka Eclipse UI and includes new widgets, new data models, new common dialogs, new layouts and much more.
Survey coffeeBeans are Swing based JavaBeans for easy component based MVC application development
Quantum is a database plugin for Eclipse (needs GEF, Point Eclipse at http://quantum.sourceforge.net/update-site). It currently supports most databases with a JDBC driver. It shows tables, views, and sequences in a tree format and provides an SQL editor
The EditorList plug-in is an editor manager for Eclipse that presents editors in a convenient view. The current release is compatible with Eclipse 3.0.x through the current Eclipse 3.2 releases.
Tracker is a widget for the Mac OS X Dashboard. It is the first widget made using Cocoa and Apple Script.
Tracks value of stocks in user's portfolio, as well as displays latest news and reports. Alerts for variances in stock prices can be set up, too.
OpenJogBlog is a tool for blogging your jogging activities. You can record data on your runs, routes, and equipment, and keep track of your progress using built-in graphical analysis tools.
DTreeJungle provides educational applets to teach the concepts of decision trees for regular pattern recognition.