I have no idea if these exist. But I imagine that the most useless chess items that anyone COULD own would be:
Milli Vanilli CD: learn chess in 6 step by step chess songs about each chess piece.
Invitation written in blood from the arch fiend of the 9th gate of hell to play chess.
exquisite chess set made of ice.
Book: George Constanza plays chess. With foreward wriiten by The Backyard Professor.
Chess clock made out of solid chocolate; its time will be short.
Patzer detection device: an electronic gizmo that beeps when any of the 100 worst chess players in the world are within a 1 km radius.
When it arrived and I saw the extra pawn I thought to myself how I would feel to get the set that's missing that 8th black pawn (I'm impatient when it comes to mail orders... waiting 3 days is like a month to me lol) 
The fact that I have 8 or 9 chess sets...
and most of my books