I don't really have any hard limits on what you use, except photography. That really wouldn't jive with the aesthetic. As much as how close you can get to the lore, just try your best. I tried to line the races up with something in popular media that would work. Are you looking for anything in particular? Because I have loads of pictures that I saved for this RP. I can point you in a direction.
Oh great. I don't have anything in particular yet, but I will definitely reach out to you for those when I decide which path I'll take. That will be much easier I think.