What if Harry Potter was not a Potter at all, what if he was in fact a Winchester? Non-canon compliant. This is from my own head, and it is what I want to write. I do not own Harry Potter or Supernatural, but I do own this story idea.
Hunters are not allowed to raise magical children. When it is discovered that Mary is pregnant with a wizarding child, MACUSA steps in, and the Potters step up. Henry Winchester is raised as Harry Potter until security concerns send him to a family that does not know he exists. As Winchester luck dictates, the road will not be smooth. Especially when Heaven intervenes.