My Printrbot Metal Simple used to wander aimlessly around the desk. The desk also acted as a resonance box, amplifying the printer noise. So I designed these little pads, printed out of Ninjaflex and now the printer stays put and is much quieter.
I used Microsoft 3D Builder to print it but any slicer settings should work. Use a rubbery (no slip) plastic.
I haven't tried printing them out of non-rubbery materials, if you print out of ABS or PLA make sure you add some sort of non-slippery coating on the bottom.
I enjoy designing minimalist-functional 3D objects.