Yes, an Apple Watch.
I was sceptical and derisive for years... then I was given one, and now I wouldn't be without it. Far better than "just getting your phone out of your pocket" as some people apparently prefer.
I use it for quick notifications of messages, calendar events, linked to various smarthome devices, laptop unlock, 2FA device, contactless payments (probably the most useful feature to me, especially when nipping in and out of, say, tube stations when fiddling with phone is more cumbersome).
I suspect I'm the wrong age to ever be comfortable taking phone calls on it, but otherwise it's a gem.