Seelie are definitely their own unique thing. They don't have a trace of human in them. Warlocks are, well, it's an indelicate way of putting it but each warlock is a hybrid. Shadowhunters are descended from hybrids, but they're generally encouraged to...keep to themselves.

[The little sniff and roll of his eyes should be enough to elaborate on what that means. While Magnus himself is involved with a Shadowhunter at home, and Alec's sister Isabelle has been involved with vampires and Seelie, most Shadowhunters guard their precious bloodlines like they have gold running through their veins instead of diluted angel blood.]

Vampires and werewolves are turned from human. Or Shadowhunter. Usually. So we have a whole assortment of options.