Darkflame Universe - A server emulator for LEGO Universe
Limon Engine - Limon is a multi platform 3D game engine mainly focusing on first person games.
Brickadia - Make anything, brick by brick.
Project Anarchy - Project Anarchy is a complete end to end game engine and state-of-the-art toolset for mobile.
Roblox - Reimagining the way people come together.
Reality Factory - Reality Factory is a free suite of game development tools for building 3D games.