A list of races that exist within the series but are hardly mentioned and/or seen.
Centaurs are a proud people not to be mistaken for padfoots. As typical in a fantasy series, they possess a horse's body but have a human torso where the head and neck would be.
Currently, only one centaur has been seen whom was serving as a waitress in a tavern.
Gillmen are an intelligent water-dwelling race. They have a distinctive resemblance to fish. They are referred to by other names such as Innsmouth, and much to their chagrin, "fish-people" and "sea-goblins". They possess emotionless bulging eyes, flippers, fins, and tridents for weapons. Their ancestor is the Octopus Lord who descended from the Sea of Stars. 
Undines are water spirits that manifest as a gorgeous woman. They can be used for shaman spells. Elves living in the forest ask them to wash their clothes for them.