[TXnMA]

As a physical chemist, I would agree that the likelihood of unidentifiable alloys is vanishingly small.

OTOH, I would not be at all surprised that there are plenteous useful allotropes of common materials that we've yet to identify and characterize.

Consider the common element, Carbon: engineers are just beginning to explore the usefulness of newly-discovered allotropes like buckminsterfullerene and graphene -- as well as higher-order microstructures such as nanotubules, etc...

I'd say we're just beginning to explore the riches of materials science!

[BenLurkin]

Interesting