class browser does not currently work for .py files, but it's still a nice IDE to use for python projects
Bluefish
Linux, Windows, Mac OS X
C, GTK+
GPLv3
The link points to the features page.
Cream
Linux, Windows, FreeBSD
C
GPLv3
Cream is a free and easy-to-use configuration of the powerful and famous Vim text editor for both Microsoft Windows and GNU/Linux.
Cssed
Unix/X, Windows, Mac OS X
C, GTK+
GPLv2
CSS editor with syntax highlighting for Python, and embeded Python interpreter. Extensible through a Python API.
codeEditor
Unix/X, Windows, Mac OS X
Python, wxPython
BSD
Extensible in Python; part of PythonCard. Includes PyCrust shell.
eric4 and eric5
Unix/X, Windows, Mac OS X
Python,PyQt
GPLv3
Complete IDE, very well integrated with PyQT development, but usable for any kind of project. Supports projects, debugging, auto-complete, syntax coloring, etc. It is extensible via plug-in system. It has interfaces to Subversion and Mercurial.