Are there really Angels? Yes. Unquestionably. I don't expect my opinion on the matter will convince anyone, though, and it doesn't actually matter one way or another if it does.

They aren't restricted to any particular religious tradition, but predate those traditions. The various religions have attempted to describe them in whatever terms made sense to the people at the time.

There are probably also various physical beings that have been mistaken for Angels from time to time, but that's another matter entirely.