VCV Rack - A cross-platform modular synthesizer.
Unity - The multiplatform game creation tools for everyone.
miRack - Eurorack-style modular synthesizer for iOS.
Godot Engine - Feature-packed 2D and 3D open source game engine.
SynthEdit - Visual programming software to build your own synthesizer.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.