Astra has an old promise ring made of thread that she was given when she was much younger (not sure exactly how old) but either she still wears it if it fits or somewhere on her person, alternatively, after she gets a home, she keeps it in a lil chest or something, along with its match.

Cotton has her old gym circuit (galar oc) thing, filled out with all the badges from about a decade ago. Its tossed somewhat haphazardly behind her other work, hidden from the eye of someone who doesn't spend a lot of time in her office.