Unity - The multiplatform game creation tools for everyone.
Mockuuups Studio - Fast and easy way to create product mockups on macOS, Windows and Linux.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Smartmockups - Create stunning product mockups, easily and online.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
MockMagic - A free, easy-to-use device mockup generator