Decentraland:  A virtual world where players can create and monetize their own content, with a focus on social interaction

The Sandbox A user-generated content platform that allows players to build, share, and monetize their own games and experiences

Axie Infinity:  A blockchain-based game where players collect, breed, and battle creatures called Axies, with real-world rewards

Roblox:  A massively popular platform that allows users to create and play games, with a focus on user-generated content

Minecraft:  A sandbox game where players can build and explore virtual worlds, with a vast player community and modding scene.

Second Life:  A long-running virtual world with a focus on user-generated content, social interaction, and commerce.

VRChat:  A virtual reality social platform where players can create and explore user-generated content, with a focus on avatar customization.

CryptoVoxels:  A blockchain-based virtual world where players can create, display, and sell art and virtual real estate

Somnium Space: A blockchain-based virtual world where players can explore, create, and monetize their own content, with a focus on VR.

The Upland: A blockchain-based game where players can buy, sell, and trade virtual properties based on real-world locations, with in-game rewards.