I chose not to use the typical Tolkien or D&D based humanoids as adversaries in my game. Typically encounters will be with humans. When humanoids are encountered they will be of the following variety:
Beast-Men: Beast men are genetic experiments from ages past that have survived and reproduced on their own in the wild. They are creatures of chaos, and they carry a hatred for humanity in their hearts for their miserable lot in life. They are represented by the stats for Gnolls from the Holmes edition. They are mostly animal headed (not restricted to dogs or jackals - could be goats, cats, etc) fur-covered humanoids. They are usually encountered in the Desert of the Dead Gods, though a few tribes have ventured farther afield to raid human and Sumalhi settlements. They rely on their thick hide for armor, though a few may scavenge armor taken from the dead. They fight with any weapons they can get their hands on. Each tribe has a shaman that leads them in their worship of ATUM'BOM the god of chaos and destruction of humanity.
Mutants: Mutants are the surviving members of humanity that were trapped in radiation filled zones after the collapse of the ancients. Their mutations stabilized after a few generations and were passed on to each surviving generation that followed. They are represented by Goblins, Orcs, Hobgoblins, Bugbears, and Ogres in my world. For every 20 encountered (regardless of type) one will be a "Wild Mutant", these wild mutants will have 1d6 unstable mutations (these can be determined by choosing spell effects to apply to the mutant or using your favorite Gamma World type game to generate a mutation for them). These mutants live in nomadic tribal groups, and some have ranged far beyond the Desert of the Dead Gods and may be encountered in practically any terrain. Some even reside in the slummier quarters of Ugarit and other city-states. They are treated as second class citizens by all however, which causes much resentment amongst the mutants. A recent cult (started by human sympathizers and lead by human high-priests) is very popular among the mutants, the Cult of CA'AMERKU the Avenger. This cult has inspired many mutants to rebel at their status in society and has caused some recent riots and violence in the upper city of Ugarit.