Humans, like all living things on Orr, have visually unique differences among different geographic regions and cultures.
Many human nations on the Arazian continent, such as Antiford, saw many years of colonization and further welcomed immigration from Paorr by different cultures (often in an attempt to push out the native Vibranni) which led to a very diverse population of humans.
Paorrian countries are often less diverse than Arazian ones. However, the region, particularly mainland Paorr, did see borders collapse during the 5th Age, the Age of Paront, and many took advantage of that to seek fortunes in lands they otherwise may not have.
Intolerance and tribalism on Orr is mostly seen on the basis of their species “race” (human, yeti, vibranni) or nationality, and far less on other factors.