gonna throw my list here:
Superstar SM / Superstar JYP - a compilation of rhythm games loosely based off of osu!mania + School Idol Festival's card collection system under the theme of Kpop. I'm obsessed af. Songs are an absolute bop
Love!Live School Idol Festival - classic mobile rhythm game - collect girls to gain more points in order to collect more girls. Simple, but addictive.
Voez - osu!mania but I'd argue the difficulty can spike harder at some points + consistently good beatmaps.
Cytus - very similar to osu! style but touchscreen.
Taiko no Tatsujin - the OG osu!taiko and gotta say, it's still incredibly relevant.
Stepmania is, as someone put it "osu with arrows"
Something a bit different is "Rhythm Coaster" I can't describe the gameplay, but it's pretty interesting when you try it out omo