Obviously one Off-Broadway/regional play doesn’t begin to take us where you’re looking to go, but it’s worth mentioning “Heroes of the Fourth Turning” in this context. A beautiful play about people and ideas seldom seen on left-leaning stages.
I don’t imagine it attracted very many people who think differently than the typical Playwrights Horizons audience. But it did give those audiences an empathetic view of “the other side.”