Are there persons born with more than one quirk aside artificially made creatures?
It's strongly suggested that many of the holders of One For All had a Quirk of their own, with Deku being an exception rather than the norm, but that's a similar process to the one that created Nomu so I don't know if you'd count that.

Other than that, the show doesn't really suggest that having more than one Quirk is something that normally happens, although a single Quirk may have multiple facets (e.g. Todoroki having both ice and fire powers, or the fact that many people have unusual bodies in addition to their Quirks).