Unity - The multiplatform game creation tools for everyone.
Vircadia - Vircadia is an open-source and decentralized real-time VR creation platform for university, enterprise, social, and OpenSim users.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Second Life - Second Life is a virtual reality platform where individuals interact in a virtual world. The software was developed in 2003 by Linden Labs. More than one million people now regularly use the software.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.
GDevelop - GDevelop is an open-source game making software designed to be used by everyone.