Blockland - Blockland is a non-competitive multiplayer sandbox-style construction game. It's kind of like playing with legos on the internet.
Roblox - Reimagining the way people come together.
Garry’s Mod - Garry’s Mod is Funny, Sandbox, Co-op, Building, FPS, Action, Single and Multiplayer video game created by Facepunch and published by Valve.
KoGaMa - Kogama is a Massively Multiplayer Online, Sandbox, City-Building and Adventure-based video game.
Brick Hill - Brick Hill is the ultimate building block game, allowing you to push the limits of digital bricks and make your own games.
Terraria - Dig, Fight, Build! The very world is at your fingertips as you fight for survival, fortune, and glory.