We've now showed a few (cropped, I know) drawings of people from the main culture. Any guesses on what it is?
If the right image above that post is typical, I would guess it's inspired by Baltic cultures, maybe with a hint of Central Asian.
There's more, of course. And then it's a question of what Gloranthan cultures this translates to. But hey, not bad.
So I guess I'm going to bite, but it's honestly kind of hard to pin this down to Glorantha. In terms of aesthetics, though, the walled village in one of the earlier screenshots looks a whole lot like Sintashta culture settlements, and the logo has a Seima-Turbino -style dagger, so along with the clothing that points pretty clearly towards the Eurasian steppes as far as source material goes. I think there were some images of shamanic masks, too, which would go well with Siberia.
On the Glorantha side of things, in the screenshot with the clan ring, the clan leader had the Fire Rune. That should narrow things down a lot (assuming it wasn't a red herring), since the only people with ruling gods associated with the Fire Rune is associated mainly with Dara Happans and Pentans. But neither of them really live in wooden houses that we've seen in some of the images here - Dara Happans are city people and Pentans are nomads with no permanent settlements. In Genertala, just about all sedentary, mixed farming clan societies that we know of are some variety of Orlanthi, and I think the only ones out of them have a Fire Rune chief god are the Caladralanders of the Holy Country, with their volcano worship, but since the area is supposed to be tropical, it doesn't really fit what we've seen of the clothing. Going further west doesn't really help either since people there are either filthy monotheists, primitive hunter-gatherers or more Orlanthi. So, I guess I'm stumped.
That said, Pent is enormous and not very well defined in the Gloranthan material, and the only thing that really seems to stick is that Sheng Seleris was totally hardcore. So there's plenty of room for some cattle-raiding Pentan societies who like to live in houses instead of yurts - if anything, you'd really expect there to be some, since they did rule most of Peloria from time to time and should've picked up a thing or two. But I'm not sure they exist in any source material as it stands!