A Grim reaper suit - Grim Fandango
Actually, I never remember the Grim Reaper suit being part of your inventory. Oh, you wear it once while playing the game, but it was no more part of your inventory then Guybrush's shoes. I don't have it now, because, I lent it to my sisters, so I can't check, but I have a good feeling I am right.
Unused inventory items
A bucket of teriyaki sauce.
A comb carved from a butternut squash
A souvenir snow globe for Hell
Slippers for your pet monkey