Spring Engine - Spring is a versatile 3D RTS game engine.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
PlayCanvas - PlayCanvas is an open-source game engine built on WebGL and WebVR.
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
Lips of Suna - Lips of Suna is a tongue-in-cheek action RPG.
Unity - The multiplatform game creation tools for everyone.