Eh, I've got a few rarer things tucked away around my bedroom. In terms of coinage I've got an American $1 coin, some round Australian 50c pieces as well as some 1c and 2c pieces and some Aussie pennies, florins etc. I just found a box of coins in my room one day so that was interesting.
For gaming merch I've got a set of Club Nintendo hanafuda cards as well as a Phoenix Wright finger stylus from Japan. I know they aren't too rare there, but they are in Australia.
From the music world, I have signed copies of Andrew Huang's (songstowearpantsto) Summer CD and Fall booklet which I had to get signed in person when he came here on tour.
And finally, my favourite rare item is a set of clear, fairly cheap Dungeons and Dragons dice signed by Taylor Swift (with one letter of Taylor on each die and Swift on the case). As far as I know it's the only set of dice she's ever signed and that makes it one of a kind in my books.
EDIT: Oh, I also have all the statuettes from the First 4 Figures Twilight Princess range, the exclusive editions of course.