So I only have metal pegboards - some are metric (25 x 25 x 6mm) and some are imperial (25.4 x 25.4 x 6.35mm). The pegs I got from the hardware store were horrible - sometimes they didn't stay in when taking the tools out and wobbled around a lot - no fun to use.
So I designed these to work with both metric and imperial pegboards. I went through at least 10 iterations to get to this, hope you enjoy, they will clip into place with a satisfying click.
Sugest printing with PETG/ASA/ABS - at least 1mm of walls/top/bottom, 40% triangular infill.