ClassyTk is an extension of Tk based on the ClassyTcl Object system. It adds a lot of improvements to Tk, ranging from drag and drop support (between Tk apps) and a configuration system to a large set of new widgets and commands, written using the object system. It also contains a GUI Builder that can be used to graphically create interfaces. It is invoked via the cbuild command in the bin directory. There are also some sample (but useable) applications created with ClassyTk: a very useable editor, a calculator, a drawing program, and more.
The Xmt Library provides nine custom widgets and over 260 convenience functions designed to make Motif user interface development easier for beginning and advanced programmers. It provides an alternative tool chain that avoids the use of GUI builders. The essence of this approach is to program from the resources file using an extended vocabulary for automatic creation of the widget hierarchy, dynamic layout, and to provide a rapid prototype environment.