I think it would be awesome if we could craft standing stones that can be placed on the ground and provide effects in a certain area, like faster mining or increased health. Or perhaps peace stones that lower mob aggression and negate PvP damage.
Obviously they can only be placed once or else people might litter stones everywhere. Deconstructing them would destroy them. Also, I am imagining them being rather difficult to make, obviously with more powerful stones being harder to create.