An underground ore vein (sometimes exposed by digging)
An underground gold vein
An underground storage (should extend 80 blocks underneath surface)
a robot bulldozer thing for digging
Perhaps something that could go on the landing pad. Probably not.
Deforest rover. Will be able to plant trees as well as cut them down.
Bulldozer, but 2x2. A powerful excavator that can reshape the surface of your settlement or bore into the ground to find buried mineral deposits.