Animalistic?
Fantasy?
Cartoonish?

If any of these, then intimidating or friendly?
I'm going to work in this, but I'm going to make some head doodles of what I can think of. Prepare FOR PUMPKIIINS.

But no, in actuality, you will not see too many abstract heads where it's a bunch of lines and two dots as eyes—I will promise you that. I will try my best to have variation of ideas according to what your parsmeters allow, however do expect a bunch of animals, and cartoon heads.