Money! Unfortunately I’m broke, but I do have a sizeable collection of foreign coins and bills. I don’t remember how it started but at some point in my life people just started bringing me their foreign currency. “Hey, I heard you like collecting coins, I got this from Algeria” “Hey, I heard you collect money, I got this from Taiwan”
I think my favorites right now are the currency no longer printed or of nations that no longer exist. USSR, Nazi Germany, Mao Zedong bills, some Eire from Ireland. I also have several misprints that are very cool, a silver penny misprint, and I have a ridiculously old bronze coin from a Chinese dynasty.
Odd shaped coins are great. I have some coins from the Bahamas with scalloped edges. Those are neat! My favorite odd-shaped one is a misprint. It’s a blank round of copper except for a small sliver on the edge that is pinched into a penny.
Unfortunately I can’t narrow down my favorite coin as there are too many to choose from.