Pyzo - Pyzo is a cross-platform Python IDE focused on interactivity and introspection, which makes it very...
PyCharm - Python & Django IDE with intelligent code completion, on-the-fly error checking, quick-fixes, and much more...
WideStudio - WideStudio is an open source, Integrated Development Environment for desktop applications purely made in Japan.
Spyder - The Scientific Python Development Environment
Thonny - Python IDE for beginners
Qt Creator - Qt Creator is a cross-platform C++, JavaScript and QML integrated development environment. It is the fastest, easiest and most fun experience a C++ developer could wish for.