Terraria - Dig, Fight, Build! The very world is at your fingertips as you fight for survival, fortune, and glory.
Reality Factory - Reality Factory is a free suite of game development tools for building 3D games.
Minecraft - A block-building game that allows you to create and explore entire worlds from scratch.
CraftStudio - CraftStudio lets you craft games from scratch in real-time over the Internet.
Roblox - Reimagining the way people come together.
Limon Engine - Limon is a multi platform 3D game engine mainly focusing on first person games.