Creativerse - Creativerse is a sandbox adventure game set in a beautiful yet treacherous world shrouded in...
Blockland - Blockland is a non-competitive multiplayer sandbox-style construction game. It's kind of like playing with legos on the internet.
Minecraft - A block-building game that allows you to create and explore entire worlds from scratch.
NERF Arena Blast - The website linked is not real page, just moddb page.
Lunacraft - Lunacraft focuses on Endless Creativity and Exploration elements.
Blocksworld Wool - Download mods for Blocksworld!