Not seen a new true one-switch game, no mouse required, for a while now. Olympics Squared from Lexaloffle puts that right. It's a cute-surreal collection of three sports events: Ski-jump, javelin and diving. Set your switch to left-click. Click pretty soon after your event starts to split into multple athletes, then again to jump/throw/dive. Once (if) you get the knack, this is quite a compelling little on-line game.
Thanks to RetroRemakes via Twitter for the link.