Thanks to My Singing Monsters, I now know—singing monsters are great! The game is a trip—it's out on iOS and Android, and you can play it for free (yeah, it's got microtransactions if you're into that sort of thing, but you can also get a lot out of it without paying anything.)
The gist is simple—it's a resource and land-management sim like a lot of other free-to-play games. You buy and grow monsters, clear out land on your island, and reap rewards from the monsters you grow. But—and this is key—your aesthetic reward for having a cool, well-laid-out farm is more than just, well, having a cool, well-laid-out farm. See, the monsters sing.
They create all sorts of cool music, from basslines to melodies to rhythmic tracks, and it's up to you to mix and match them so that they make the kind of tune you want. In the niftiest touch of all, the music you play depends on where you are on the map, so you can control the stereo pan of your tune (or make an entirely different tune altogether) by moving around on the map.
My Singing Monsters [Apple App Store]
My Singing Monsters [Google Play]