Blackvoxel, an ambitious Minecraft/Factorio mix?
Check out this interesting (somewhat recently GPLv3 re-licensed) game Blackvoxel : As you can see it has some interesting mechanic which they call " Molecular Voxel Interaction Engine ". As seen in the trailer above, it basically allows you to automate crafting, resulting in interesting "programmable" factory setups. Of course this might sound a bit too much like actual work and not fun... but given the big fan scene for the closed source game Factorio , I would say it can be more fun that it looks at first ;) Blackvoxel itself probably needs to be a bit more of a game instead of "just" a sandbox, but there is big promise in the overall concept, so give it a try :)