Harry Potter / Fantastic Beasts Theory
So I heard that there is a fan theory out there about Harry Potter actually having a minor Obscuris. As in, whenever he did things subconsciously (i.e. the glass in the snake exhibit, appearing on a roof, etc) that was actually his Obscuris.
Not quite sure I believe it, but it is an interesting concept. He was certainly mistreated by his Muggle relatives, and untrained, but he went to Hogwarts at the usual age of 11.