The World of Xoth is an early discovery of mine; a sword & sorcery in the very old-fashioned sense. The author of it came to my attention many years ago for his work online in converting D&D (Third edition) to Hyboria; the setting of Conan. He later decided to dabble in his own version of a Hyborian-like setting, which is World of Xoth, I've had the map and read a handle of blog posts on it years ago too. Which is why was surprised when I stumbled across it more recently and discovered that there was content I had never seen before, including a newer high resolution map, and a 60 page pdf of house-rules that updated the system to Pathfinder... and then did some stuff to it. Most of these house rules would have worked just fine for d20 too, for that matter.
MAMMOTH LORDS setting; which does for the New World, kinda, what the Hyborian Age did for the Old World.
To wit; the World of Xoth is a humanocentric, classic sword & sorcery setting, which means that there are no racial choices that are mechanically meaningful except human. There are a number of human races that you can choose from, but they all have roleplaying hooks only, not mechanical hooks. However, each race will tend, and usually with only extremely rare or even nonexistent exceptions, fall within one or maybe two different "cultural archetypes." And there are mechanical implications to your cultural archetype. He uses a spectrum of cultural archetypes, starting with Savage, and progressing from there to Nomadic, Civilized, Enlightened, Decadent to Degenerate. His pseudo-Vikings, for example, are "mostly Savages" with "some clans and individuals are Nomads as well as rare Civilized half-breeds."
I quite like this idea, and I think I'll adopt it to MAMMOTH LORDS; it has a really iconic sword & sorcery feel to it. But I'm not sure that I want to think too much about MAMMOTH LORDS when I'm trying to figure out exactly what to do with my "space wizards" from AD ASTRA.