Got 5 pairs of Kitty slippers, 3 umbrellas, bunny hoppers coming out of my ears and enough whoopee cushions to sink (or refloat) a battleship.
Doesn't even need a reroll mechanic, just something to do with all my spares (Running out of armour stands).

I'm still not really sure if this is a problem that needs to be addressed, since could argue that the same issue applies to vanilla items you can only find in chests like saddles and horse armor. A rerolling mechanic in particular is something I'm not interested in adding, as I think this would discourage players from exploring in different places.
I'll keep this issue open for now though.