Just one, an old LG 3G smartphone that was my first smartphone two smartphones ago. I should also have my previous smartphone, a Droid Razr M, but I let my grandson borrow it a few years ago when he broke his phone, and I never got it back once he got a replacement.
My wife, on the other hand, has about three or four old Nokia Windows phones in a drawer somewhere. Neither of us have any old flip-phones, we recycled/donated those years ago.