There's supposed to be other Miraculous holders- but the only one I've ever heard of outside me and Ladybug is Papillon, he has the butterfly one. But he;s also the guy trying to bring Paris to its knees ever other day- so not going to be helping us on the hero front ever.

...There's a fox too, but I've never seen them. Probably a couple others, as well. But I've never come across them in the flesh.

[Volpina absolutely did not count, she was an illusion- which was ironic when he really thought about it.]