Rare but do exist. Lizardfolk and Yuan-Ti mostly in Everwoods, Kobolds in the southern lands, Memnos and Xenera. Haven't really thought much about many of the other races but you can find places for them. They should probably be used much like they are presented in monster-books. But Dragons, now were talking. Dragons got pretty much annoyed by all these fastbreeding pests and moved to a land isolated by mountains and the desert, south of the map I provided. There are few hanging around Everwoods, few in the mountains and even few disguised as humans and living in the cities. But most of them have isolated themselves from the world.
In ancient times there was a religious order called the Dragonites, who worshipped dragons as deities and even made pacts with young dragons to carry them in battle. The order still exist but nowadays most of the Dragonriders ride wyverns because true-dragons are so rare. There are a few exceptions to this also.