Kidblock!

Minetest is a near-infinite-world block sandbox game and a game engine, inspired by InfiniMiner, Minecraft, and the like.

Terasology (started under the name Blockmania) is an open source project started by Benjamin “begla” Glatzel to research procedural terrain generation and efficient rendering techniques in Java using the LWJGL. The engine uses a block-based voxel-like approach as seen in Minecraft. After proving itself as a solid tech demo begla was joined at first by Anton “small-jeeper” Kireev and Rasmus “Cervator” Praestholm and a full-fledged game concept was born.

The Fun-Focused Free Software Voxel World Game.

Mythruna is a game under construction combining extensive world building, crafting, and sandbox elements with just a touch of role-playing. When completed, Mythruna will be a unique gaming experience.

Cube World is a 3D action RPG currently in development for PC. It features a huge procedurally generated world made up of cubes!It may look like another Minecraft clone but this is more down to exploration. Find roads leading to a village. Get quests and talk to NPC's. Its inspiration mainly comes off of Legend of Zelda, but open world.

Creativerse is a sandbox adventure game set in a beautiful yet treacherous world shrouded in mystery. Adventure solo or bring your friends, unearth secrets, and tame the land together!

Freeminer is a Minecraft-inspired sandbox game.

Blockland is a non-linear sandbox game with no set goals, giving players the freedom to design and construct elaborate structures. Styled as a tiny minifigure, players build inside of the virtual world using bricks reminiscent of toy blocks. These structures can be built in either a single-player or multiplayer (either online or through a local area network) setting.

Manic Digger is an open-source implementation of block-building games, like the famous game Minecraft.Manic Digger aims to be a generic platform ontop of which you can create your own game-types and scenarios. Through server-side scripting, almost any type of block-building game should be possible.

Minecraft Clone to PSP

Make the world truly yours in Junk Jack, a relaxing sandbox experience focused on building and improving your home. Discover new planets, tame and breed creatures, cook foods, collect animal companions, farm exotic plants, collect fish, grow flowers, play with your friends!

Infiniminer is a multiplayer block mining game with several different player classes to choose from.The object of the game is to collect loot while trying to keep the other team from accumulating loot.

MineDroid is a viewer / concept design for Minecraft that supports using your own 1.3 beta levels, temporarily building and destroying blocks, sensor steering, crouch jump, ghost mode / fly mode. more features to come, you can get the source and help out too

Eden brings the creative block building genre, pioneered by games like Minecraft, Infiniminer, and Blockland, to the iPhone and iPod Touch. Build your own personal Eden.