Here is a small square plant stand that I made for my wife's string of pearls succulent that is in a small square pot.
It lifts the pot up to keep it off the shelf and has a lip for watering. It is goblet shaped and lets the plant dangle gracefully around it. It's modeled pretty small, but there is no reason that you couldn't scale it up if you wanted it for a bigger plant.
I designed this using Solidworks and printed my example using Hatchbox wood PLA for a nice natural look that I think turned out nicely.
The author marked this model as their own original creation.