Lately, we've seen DnD and Pathfinder move away from some of the more blatant signifiers, like renaming "race" into "species" and "ancestry," and in the case of Pathfinder, having systems in place to mix ancestries in a character build. DnD has decoupled good and evil from species, and pathfinder has done away with good and evil entirely ( keeping a vestige of it present for things like demons and angels).
Race is almost alwys tied to a language and a culture, with, say, kobolds having the same certain cultural signifiers all over the world. To an extent, this makes semse because different peoples in these games can have different physical abilities, or have different origins entirely, which would naturally lead to them developing along different lines -- If one people can breathe underwater and another was born from a volcano by a specific god's decree, that would inform how these cultures behave.
Is it possible to have a fantasy along these lines with a materialist underpinning, or is this very idea of inborn powers anathema to that sort of approach?
You may be interested in some of the lore and mechanics around Sigil. It doesn't exactly escape the D&D tropes (in some sense it's at the center of the universe, in a universe where good and evil are physical places you can go), but it does present a framework for an actually politically and culturally diverse metropolis. It's also a city of infinite portals, so you can kind of make things intersect with whatever story you're trying to tell. The Bleak Cabal are kind of vulgar materialists, the Athar are anti-theists (or anti-divinists, or whatever), there are multiple flavors of anarchists, labor unions, and there's all the extraplanar politicking and backstabbing you might need to keep things spicy. I think the authors of the Planescape setting managed to avoid some of the worst real-world tropes of your average D&D setting, and the spiritual successor Numenera may be more actively positive in this direction.