41 Games: Chime
This is one that's been part of my backlog for 5+ years.
Chime is a small, meditative game about filling empty space. It's not exactly right to call it a rhythm game, but music is critical to the experience. As you connect shapes to fill the blank space on the board, the music gains new tracks, filling the audio space alongside the visual.
It was made originally to raise money for charity, so it only features a few songs. And I think the default mode's time limit is a little too long, risking monotony. But it's a different take on music games and a good way to zone out for a few minutes at a time.