OH BOY I LIKE THIS THREAD...
Angels: My angels have a few types. There are angels from Heaven, who have a humanoid form covered in wings and eyes. They take on human forms to visit earth. Remiel, who was temporarily barred from re-entering heaven until he changed his ways, maintains this type of form, sans wings.
There are then angels from paradise, which is not really heaven but certainly feels like it. These "angels" take on human forms, but their true forms are those of monoliths. In other words, angels from paradise are just floating, telepathic chunks of rock and gemstone. Sigourney Alice was created from one of these monoliths, but is half human and therefore shunned by them.
Demons come from a caste society. Hell is structured carefully, each demon in their place. Yves is a demon from a medium caste, as he has some small amount of succubus blood in him. Helvetica, on the other hand, has mostly imp blood, and is extremely low ranking. The highest ranking demons, aside from Lucifer and his family, are Maidens, consorts to Satan who have gone through a series of painful trials to become his "brides." Next come nobles and high ranking war demons; lower nobles, succubi, cultists, and then imps and lower class demons. Demons can move through the ranks, but not easily. It is definitely much easier to be de-ranked form a succubus to a minor imp than it is to go from impdom up to nobility.
Vampires I haven't suuuuuper developed the lore of, but they all have pink eyes (because I like the look.) In the coven I'm developing, they keep humans as companions who willingly allow the vamps to drink from them; in turn, the vampires take care of them as well. They are a bit like parasites; their souls can leave their bodies and hitch a ride on a human host body. If a vampire's body was to be destroyed beyond repair, they could survive, so long as they make it into another body in time.
Oni are a species I've worked on a loooot. They're rather froglike, descending from Roke, who were polliwog like beings several thousand years ago. As a result, they worship frogs and other amphibians. I have a lot of info on them here actually!
Witches since I just saw them mentioned above: Most of the witch types I write control elemental magic. ( Calvin is the exception to the rule, being a more traditional, all-around witch. ) Alexandira in particular is the avatar, master of the four elements a witch who controls water fire earth and air. She also controls music magic, using a harp for protective spells. But she would be unable to use her harp for elemental magic, or her staff for protective spells. Different objects have different abilities, basically, and those weapons are required to do magic.