yeah I have heard of the zoomatar 240mm f/1.2. That lens would have been had the weight of four bricks lashed together with duct tape. There was the Ermanox, which was a 645 plate camera with a fixed 10.5cm f/1.8 ernostar lens was remarkably fast for such a large format in 1924:
But nothing that fast has ever been commercially produced for medium format in the past 70 years. On LF there are some Aero Ektar* lenses that are suited for use on 4X5 cameras a f/2.5 are
very fast, that is one way of getting even shallower effective DOF than a 50mm f/0.95 lens on 35mm.
* Early versions of these lenses are viciously radioactive.