Unity - The multiplatform game creation tools for everyone.
GCC C Preprocessor (cpp) - Top (The C Preprocessor)
Godot Engine - Feature-packed 2D and 3D open source game engine.
PP - A generic Preprocessor - P is a text preprocessor designed for Pandoc (and more generally Markdown and reStructuredText).
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
xmllint - command line XML tool