Sets of keys are very individual. Some people carry only a few while others would make a fortune at the scrapmetal yard 🙂
I think keys can be a great story starter, offering lots of clues as to the owner. Try putting an anonymous bunch of keys in the middle of the table at your next writing group meeting as see what stories you can come up with. Perhaps the characters will be similar to the owner of the keys or perhaps very different.
And . . . the owner of these keys? My son Pip 🙂