I didn't know that handcuff keys are universal.
Just looked through my bag - the oddest thing there is probably a wooden clothespin. It... Let's just say it was never used to hang clothes.
I carry around a lot! My bag weighs maybe 15 pounds. I carry things I need like EpiPens, medications, snacks, a tote bag, a rain poncho, my tablet, etc. The weirdest thing? I don't know if this counts but I carry two Narcan in case someone else needs it.
Handcuff key, after the 3rd time calling to let someone out, they give you a key. Out-of-place-est thing I can say without trouble is that I regularly carry a comprehensive first aid and suture kit.