Have a limited amount of items to be placed around the world without the use of a core. Think of lightning/signage in a mine or maybe even cargo boxes. You could limited it to only owned territory (personal and other territory with build rights) to reduce the spamming of these things in public spaces.
I am thinking of items like:
Signs - snaps to voxels to indicate paths or closed corridors in mines. maybe even decorative once like safety signs.
Lights - Can be standing lights or lights snapped to voxels. Can be used to indicate paths or light the dark mining shafts. can also be made with batteries or that you have to link them to a reactor on a static core.
Small items like cups - So I can decorate my office.
I envision the cargo boxes in 4 sizes mostly because I think the act of loading and unloading cargo would be so much more immersive.
Small box - Hand held. Can easily move around while holding. but has only a very small amount of storage capability.
Medium box - Roughly 2x2x2 the size of a small box and will limit the player movement.
Large box - Needs a vehicle (forklift designs will be booming) to move and comes in different shapes. roughly 3 times larger than a medium box.
Extra large box - basically a shipping container.
