Minecraft - A block-building game that allows you to create and explore entire worlds from scratch.
Roblox - Reimagining the way people come together.
LEGO Worlds - LEGO's Minecraft competitor
Terasology - Terasology (started under the name Blockmania) is an open source project started by Benjamin...
Infiniminer - Infiniminer is a multiplayer block mining game with several different player classes to choose from.
Minetest Game - Basic game for Minetest engine.