Self-Adhesive Felt or Rubber Pads
Self-adhesive felt or rubber pads are readily available in the furniture section of your home center near the casters and furniture glides. You can choose between small dots, larger squares, and even full sheets that you can cut yourself. Felt pads will slide more easily while rubber pads will grip the table.
It really doesn’t matter which kind you use, though I like to get the thicker ones that will lift the coaster a little farther off the table to prevent heat and moisture from coming through.