Since the thread seems to have turned into a "what ya got" kind of thing instead of what happens to them, let me add that I have three. Two were by design and one by accident.
The ones by design are a .416 Taylor and a .458 American (aka .428x2). Both because I always wanted one although I have no practical use of either. Some claim the American has been standardized by the .450 Marlin but I don't agree. American brass can be made from just about any belted case (I used 7mm Rem Mag mostly) while the Marlin requires specific brass. I bet 20 years from now you won't be able to find brass to feed the Marlin but feeding the American will never be a problem. No fancy dies required for the Taylor or the Marlin.
My by accident is a .257 Roberts AI. Bought a Sears version of the Win Mod 70 and it had a bulged barrel. Saw a Mod 70 257 Rob barrel on Evilbay. When it arrived it was clearly marked and rechambered as an AI round. Screwed it on and wha-la another wildcat.