Unity is described as 'Real-time 3D engine enabling collaboration to create immersive, interactive experiences on Windows, Mac, and Linux, with extensive platform support' and is a very popular game development tool in the development category. There are more than 100 alternatives to Unity for a variety of platforms, including Windows, Linux, Mac, Web-based and iPhone apps. The best Unity alternative is Godot Engine, which is both free and Open Source. Other great apps like Unity are Unreal Engine, Stride Game Engine, GDevelop and CRYENGINE.
Limon is a multi platform 3D game engine mainly focusing on first person games. Focus of its development is ease of use and ease of study. It has builtin editor for maps, animations and GUIs.
VERGE is a Game Creation Engine: A progam that exists to help you make games in 16bits like super nintendo.
