Angel

Angels are considered, by those who make it there business to inquire, to be "spiritual" beings rather than magical ones, their nature and powers deriving from supernatural sources rather than what we might call preternatural ones. Not everyone agrees with this (particularly atheists and freethinkers), but it's a fairly mainstream view.
(If you want to get technical, what's in view here is that angels are believed to be endowed with their mysterious qualities and powers by God, whereas fairies and the like are thought to derive their mysterious qualities and powers from the break in reality that is called strong magic. Needless to say, some religions find this distinction more important to maintain than others.)
Angels usually have wings of some kind. Sometimes they have a lot of wings, in fact. Some people have tried to classify them based on this, but it's difficult since they're unbelievably rare and also very cagey (see below). Angelologists do report fairly well-documented sightings of possible seraphs, cherubs, and even ophans. Beyond that, it gets into rumor and speculation.
All of this is complicated by the fact that angels are notorious for their refusal either to confirm or deny that they are, in fact, actual angels. In fact, this whole thing may be something we collectively made up to explain a bunch of ethereal fairies. Or maybe not. The one thing we can say for sure is that you're not going to get a straight answer from any purported angels. Assuming, of course, you are able to find one. These curious beings interact but rarely with humans (with one notable exception)--although some scholars have tried to suggest that human clairvoyance is a kind of angelic revelation, undoubtedly in an attempt to make it more respectable by removing its magical associations.
Most angels appear to be benevolent, but there are some (often called Watchers) that impress observers with a deep, visceral malevolence. Watchers have been spotted near the sites of natural disasters and battles, but also just sort of... around. Watching. Maybe doing something invisible. Probably being evil. Definitely being scary.
The one possibly-an-angel that interacts somewhat regularly with humans is the Dream Man, the governor of the realm of human dreams. His mansion is difficult to find, and he is often wandering about tending his massive flock of dream-sheep, but clairvoyants report interactions with him just often enough. The story goes that he was set to govern the dreams either as a reward or punishment for some role he played in the War of Heaven. Naturally, he refuses to discuss this theory, preferring to chat about your dreams over a nice cup of jasmine tea.

Genetic Descendants

• Seraph