Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
VRChat - Create and play in virtual worlds with others
Unity - The multiplatform game creation tools for everyone.
Spatial - Collaborate from anywhere in AR
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.