The last one I bought was called "Uralt Kamerateil oder sowas?"
But they're often called something with "Iris", "Universal", and "Lens mount" in it in whichever order.
Most of them seem to have been made in Germany. In my experience they are often cheaper when attached to a camera than alone. Two of mine came that way; and then the camera was just too nice to get rid of so I bought another one...
Yeah, they usually go for premium prices these days. Everyone needs one to mount a lens recently acquired from Jim G.