Not really music but meta-music: I recently learned that Spotify lets you organize playlists into folders, which I didn't know before. Previously I'd been very hesitant to make too many playlists because I didn't want them to become disorganized, but now I've made a whole bunch of playlists containing music I just hadn't been listening to because I didn't have a system for reminding myself that it existed.

Just so this comment contains an actual music recommendation, Pentatonix is a lovely a cappella group.