Numenéra: Gift of the Calimshan
Abhumans were probably once Humans. This is the catchall term for mutants, crossbreeds, the genetically engineered, and their offspring.
The most common Abhumans are the Chirog, the Margr, the Murden, the Sathash, and the Yovok. These abhumans are not available for Player Characters in this campaign.
Mutants are available for play, and you can consult the entry for them to see more.