Terraria - Dig, Fight, Build! The very world is at your fingertips as you fight for survival, fortune, and glory.
Unity - The multiplatform game creation tools for everyone.
Starbound - This action-adventure platformer throws you into a procedurally generated galaxy where you can make your mark.
Godot Engine - Feature-packed 2D and 3D open source game engine.
Deepworld - Deepworld is a massively-multiplayer 2D crafting adventure game.
Blender - Blender is the open source, cross platform suite of tools for 3D creation.