python-pmw (Python Megawidgets, based on top of Tkinter)

It is a toolkit for building high-level compound widgets in Python
using the Tkinter module. It consists of a set of base classes and
a library of flexible and extensible megawidgets built on this
foundation. These megawidgets include notebooks, comboboxes, 
selection widgets, paned widgets, scrolled widgets and dialog
windows.

The base classes and most megawidgets were written by Greg McFarlane
(current maintainer) and Peter Munnings. There are also several
contributed megawidgets.