The Humans of the Known World are pretty generic. There are many different ethnicities, just like on our world. and if you read through the Gazateers it is obvious which real-world cultures they emulate.
Essentially any real-world culture you wish to emulate, there is a race of humans that are equivalent to it in the known world.

Thyatians

  Thyatians come from the Empire of Thaytis. This is one of the 2 Large Empires of the Known World, However, due to the nature of the empire, this race of people may actually be found almost anywhere in the world. They are known for their treacherous politics, and this may cause some of the race to move away from their empire.
  Thyatians have a light olive skin tone and light to dark brown hair. They are known for their
large noses. Their native language is Thyatian, which is considered Common for most of the Known
World.

  One Thyatian trait may come as a surprise. The Thyatians, among all the civilizations of this part of the world, are the fastest to embrace new cultures and races, mingling them with their own with delight and interest. Thyatians love exotic cultures, races, fashions, and customs. When contact with a new culture results in the sudden appearance of new cults and sects, clerics and scholars eagerly rush to learn about them, to contrast and perhaps combine with their own.
  When conquering or meeting new peoples, Thyatians are quick to write down the history, legends and folklore of these peoples, to intermarry with them, to absorb their arts and culture. Sometimes Thyatian conquerors end up, after a generation or two, being indistinguishable from the natives.
  So the Thyatians cannot now be said to be a “race.” The races which blend in the Empire include the hardy olive-skinned members of the original Thyatis, Kerendas and Hattias tribes, dusky Alasiyans, fair reavers from the Northern Reaches, dark-skinned Nuari from the Pearl Islands, red-haired barbarians from the Hinterlands of the southern continent, copper-skinned common Alphatians from the Isle of Dawn, and even elves of Thyatis’ western forests. Each of them enriches the Empire’s culture, arts, entertainments, and history. Dwarves and halflings are welcome in the Empire as well, and add to its culture and learning, but cannot intermarry with humans or elves.

Thyatian Humans follow the same Human Rules found in any Edition of the Game. Please look in the Player’s Handbook or Player’s Guide of your preferred Edition