Firearm auctions are pretty common. High bids are definitely often about person/legend/myth, like being at a famous battle, but many others are pretty much just the gun. I think that's because they're relatively common, affordable, usable, and easy to preserve. There's one Girl with a Pearl Earring made of canvas but millions of wood and metal Lee-Enfield rifles.

Cars seem like they'd be similar but I don't know any car collectors. I've also heard of antique furniture auctions, very curious what those collectors are like.