Found this great model on printables: https://www.printables.com/model/441984-skateboard-holder
Printed in PETG with 50% gyroid infil. I did 3 perimeters and that seems good for the regular skateboards. If I hang my longboards I will use more perimeters I think.
Thanks for sharing the files. I just found my skateboard from when I was younger and wanted a way to display it!