Ιn the philosophy of quantum mechanics some authors who are wave function realists (i.e. who believe that quantum states have an ontology which is independent from our knowledge about them) claim that the "universal wave function" belongs to a unique ontilogical category which is nothing like anything else we experience.

They make this claim in response to other views about the ontology of the wave function as a field, a law, a blob etc. since all these views face important difficulties.

So I guess there isn't a yes or no answer to your question.It depends on what kind of metaphysics one adopts. I guess a better question would be: do we have reasons to believe that there are physical entities of a unique ontology?

Ιn the philosophy of quantum mechanics some authors who are wave function realists (i.e. who believe that quantum states have an ontology which is independent from our knowledge about them) claim that the "universal wave function" belongs to a unique ontological category which is nothing like anything else we experience.

They make this claim in response to other views about the ontology of the wave function as a field, a law, a blob etc. since all these views face important difficulties.

So I guess there isn't a yes or no answer to your question.It depends on what kind of metaphysics one adopts. I guess a better question would be: do we have reasons to believe that there are physical entities of a unique ontology?