A while back, and I mean a LONG while back, Proko released a free file of skully skull images in jpg and png format. It was great. The skulls were in male and female variation, and in various minute angles. But sadly, I lost my file at some point. I was going to trace over the images in Procreate, adding the muscles -- and then the fat pads -- on top. Would anyone happen to still have this file and be willing to share it?

A common thing I've read is that when drawing hair, you don't approach drawing each hairstyle the same way. Which makes sense. You don't approach illustrating the illusion of a shaved head the same way as a full head of curls. So I think it would be incredibly helpful for aspiring illustrators to learn the various ways that professionals create the illusion of the various hairstyles at varying lengths.