GorillaPads Non Slip Furniture Pads/Floor Grippers (Set of 8 Non Skid Floor Protectors) Pre-Scored to Cut to Multiple Size, 4 Inch Square, Black, CB140-8

Furniture/rug gripper foam. I use https://a.co/d/0dnbRmoE - Slipstick Gorilla Pads. They're pre-scored but I have a solid riser on my footplate so it's not a problem. Works fine without shoes!