I really enjoy Mario Wonder, it is very varied and gets better the further you progress. I just progressed through world 3, but did not complete all levels prior (meaning not all coins, flags and seeds, I will eventually revisit some for completion). Easily the best 2d platformer by Nintendo in decades.
I am also glad Nintendo isn't sticking to their "basic Mario" worlds/design anymore. A lot of recent Mario games all had the same enemies/worlds/look etc. Especially around the time Mario 3d Land, Mario 3d World, Mario Luigi Paper Jam etc. came out.