My very first tennis racket. It was an old 70s wooden racket from my parents. I have it framed in my living room, looks really legit like a true piece of history
My nylon guitar. Wasn't my first guitar, but it was my mom's guitar for several decades. I have 10+ guitars now, but that one has the most meaning to me.
Those two are probably the most sentimental things I own. I try not to keep old stuff in general, since much of it is unfashionable, tacky or not very useful in today's world, lol.. So everything else has either been tossed (of course those are really pointless stuff) or stored at my parents' house.