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.
Chudo Virtual Spaces - Play around, meet friends, study or party with avatars!
Vircadia - Vircadia is an open-source and decentralized real-time VR creation platform for university, enterprise, social, and OpenSim users.
VRChat - Create and play in virtual worlds with others
Unai - A VR headset & world designed for real social interactions
Unity - The multiplatform game creation tools for everyone.