Most non-human sentient species and many magical beats are fey creatures. That is, they originate in the magical places known as Feyshores and have have an element of the supranatural about them. a number of them are immortal and do not die of old age; the rest are very long lived.
Some fey have spent so long in the mortal world, as a race, that they have become more like mortals.
While most fey are capable of reproduction in the normal manner, some seem to have a more spontaneous origin within they feyshores. Like everything fey this is mysterious at best.
Fey creatures vary immensely, indeed it seems to be part of their nature to embody change, chaos and unpredictability. Nevertheless it is possible to divide the fey into very broad groups: the most notable being Elves (sometimes called the Seelie) and Goblins (sometimes named Unseelie).
The Seelie includes Elves, Eladrin,
They are usually human sized and beautiful (in a slightly alien way) to humans. this is not always the case though – Dwarfs, for instance, claim to be seelie. Not everyone believes them, but they won’t say to their face.
The Unseelie include the eponymous Goblins (and all their subtypes), gnomes, fomorians.
Goblins are so variable that many people mistake them for a range of different species; for instance kobolds and kenku. This is not helped by the fact that goblins often exhibit animal traits, looking like a pig, or a lizard. Two goblins can be brothers and yet fall into completely different types.
Some goblins types do breed more true and congregate in communes of their physical brethren. Kobolds are the best known for this, tending as they do towards a love of underground places and a reverence for dragons.
Other types of fey exist, but their relationships to the above is more mysterious and not fully understood. The fey themselves do not talk of it. One of these types are spirit-fey, such as nymphs and sprites, that as well as some relation to seelie have even closer ties to nature and do not seem to need material forms.
There is also speculation that elementals are related to spirit fey in some manner.