J.B.
They sell table cloth pads at most stores that sell home goods...Walmart, Kohl's, Bed Bath Beyond, probably Christmas Tree Shops. There is usually a felt-like material on one side and vinyl on the other. The felted side goes against the table top and grips it. The vinyl side is face up and offers a water-proof barrier under the cloth to protect the table. The vinyl side is usually textured/lightly quilted to provide a surface to grip the cloth and prevent it from sliding. They're sold in multiple sizes or you can cut to size.