For my proposed Atomic Kingdoms campaign, I look forward to allowing PCs of the following races:
Elves exist in three major strains. The Ios are like the traditional elves, only their gods have all died and they lost their homeland to human invaders. The Nyss come from the far north and have adapted to arctic climates. And in a radical departure from Iron Kingdoms canon, I decided to make the Orgoth a race of elves too, as akin to the Drow as the Ios are to the "standard" elves.
Dwarves are much like dwarves in any other setting, except with machine guns.
Gobbers, who are based on the goblinoid stereotypes. Skilled at hiding, theivery, and "bodging" together technology, they fill the role of "annoying short guys".
Ogrun are large, loyal fighters.
Satyrix, who are hostile amazon warrior with great horns growing out of their heads. In the Atomic Kingdoms era they have rebelled against their former overlord, an evil dragon called Lord Toruk, and after losing a couple of wars have ended up scattered around the world, hunted by Toruk's more loyal servants.
Trollkin are a powerful PC race, and are well-respected by followers of the goddess Dhunia.
I could consider other races on a case by case basis.