Wanted to make my own Dice Tower for D&D so here it is! I sculpted it in Nomad Sculpt on my Android tablet then exported it as an STL. Will fit most dice unless they're super large. Prints pretty nicely without supports. You "Might" get a little funny in the overhangs just under the top jaw and the hole where the dice fall out, but nothing terrible (IMHO.)
I used the "Infill Support" option in CURA to put internal support only where needed. If you've never used this option, give it a try, it's pretty neat. This GREATLY reduced my printing time. You really only need internal support under the nose and the very top of the skull. Or, you could just use regular infill at perhaps 10-20 percent and let it fill the whole thing.
I used 3 walls with my .4mm nozzle (1.2mm total wall thickness). This seems to keep things pretty sturdy.