Opensource

From the Luanti/Minetest games, I also like Exile very much.

It is a bit hard and nerdy (you'll have to read the PDF guide/tutorial as you progress), but I found it calming somehow, though you're always in some crisis. I recommend single-player only.

In contrast to other Luanti/Minecraft-Like games, in Exile it feels very rewarding just to have found shelter from a storm and a cozy fire going, after you were on the edge of collapsing from exhaustion. Though you're almost certainly out of food and it would be dangerous to go out looking before the storm passes, you're not quite dying yet and you have time to make your mud hole a bit more cozy. (It's not a good game if you want to build huge creative castles, but you'll need to build and improve your home a bit.)