"Skateboard Tape" is sold in almost any hardware or home supply store as "Suretape Anti-Skid Tread Tape" to improve footing on stairs, ladder treads, skateboards, etc. It came in a 15' x2" roll with a strong adhesive backing for a few dollars.

The first bikes I got for my granddaughters had very slick plastic pedals and their shoes were always slipping off. I wrapped each pedal in Suretape using both the adhesive backing and a couple of small sheetmetal screws to keep it in place. It solved the slippage problem completely.