Three Races
The Three Races are gargoyles, humans, and Oberon's Children, the three known sentient species native to Earth. Gargoyles were the first to appear, followed by humans. Greg Weisman writes, "the Children incubated in magic and 'evolved' third," hence another name for them is 'the Third Race'.
Gargoyles and humans both came into existence in the same way, but Gargoyles makes no statement as to whether this was by evolution, creation, or both.
New Olympians are a hybrid race, and fall somewhere between mortals (generally humans, but also other non-sentient species and perhaps gargoyles as well) and Oberon's Children, rather than as a separate race of their own. There was another race preceding all three of these, nicknamed the Lost Race, but it is now extinct; we do not as yet know what it was like, or how it ceased to exist.