Fairy

This term (and various related ones in non-Anglophone cultures) refers to anything that is magical, probably though not always humanoid, and more likely to be considered in some sense a person by your average suspicious human being. There are infinitely many ways of classifying fairies, many of which derive from human mythologies, but there are also always fairies that defy classification. Nowhere, perhaps, is it clearer than in the case of fairies that much of Menagerie taxonomy is a loosely-fitting structure imposed on a more chaotic reality.
In general, while fairies have social arrangements not entirely unrecognizable, they also don't operate by human ethics or norms. Many, though not all, hold the exchange of favors in high esteem. They are especially cavalier with human possessions and lives, a fact that has earned them the undying enmity of many human cultures. While it's not true that all fairies steal babies, it is undeniably true that some of them do.
In fact, in many places human hostility towards fairies has transmogrified into a refusal to allow or acknowledge fairies in their towns, which has in turn had the curious effect of rendering fairies invisible in these towns. This, of course, becomes a self-reinforcing loop, as human inability to perceive fairies in cities reinforces their belief that fairies are only to be found in the country, and so on.
Fairies, unlike humans, can cajole the forces of the universe into doing magic, though their methods are usually a closely-guarded secret (or... are they? Maybe it's just that all of our useless magic spells work for them, and they're not telling us). Also, true fairies don't dream, though they can get into human dreams through their secret roads.
Many scholars also argue that the term "fairy" is best applied to the beings that migrated into the world during the dissolution (literal, not figurative; Fairyland basically dissolved) of Fairyland, well after the Crisis. Kind of hard to prove that, though.

Genetic Descendants

• Fairy Lion