Depends on elements of Samdstorm but yes a lot of stuff would likely be appropriate.
2E didn't have genasi in it but it did hint at elements people SE of Balic iirc.
This not appropriate magi tech, outer planar stuff, default dragon things, metal and water/food immunities things.
Adding Warforged to Darksun is kinda silly even if you buy into making them out of wood and stone.
Barbarians in theory as well not all subclasses for of course.
Sorcerers, Warlocks also fit at least theoretically if you gave them Athasian options and they follow defiling rules whatever those rules are (they don't have to be exactly like 2E except creating ash imho). Warlocks would be Uber rare.
Any organic race could also fit as long as they're mutants and you don't plop a major settlement. This could also be the extinct races but you're the only one.
Racial restrictions also push the new options to the front eg Kreen, Half Giants, Muls