I bought a 5-tier plastic shelving system from a big brick and mortar store, however, I didn't need the full 6 foot height. I made these ‘footings’ just to help stabilize the load for the remaining two shelves. I don't plan on putting much weight on these shelves so the PLA should hold up just fine.

The 3MF file fits about a 43MM diameter post. Feel free to adjust your size as needed.