I inherited a lovely old Craftsman 24" adjustable wrench from my Dad's stuff.
I've never once used it on a fastener. It has been deployed a few times for bending metal. But mostly it just hangs there and looks cool. Dad may have used it on plumbing or something.
If you want truly useless, the winner in my garage would be this gorgeous, beautifully made right-angle low-profile screwdriver from Motion Pro, intended to reach carburetor adjustment screws deep in the bowels of motorcycles. It has a selection of bits, a nice detent system and markings so you can theoretically tell how far you've turned the screws, etc.
But in every instance I've tried to use it, it's useless. There's usually not enough clearance for the head. On the rare occasion you actually can reach the screws, you can't see or feel whether you're actually engaged with the screw, or whether you're actually turning the screw, or how far. Add in a running, vibrating engine and it's just completely hopeless.