Hemera 
I had the idea this morning that I kinda want 'programmable' playlists (I wanted to say 'algorithmic', but that's been used already).
So things like:
- Play this song first:
- Take up to 20min from this playlist
- Play this song last
And you can go quite deep with this etc...
Super niche lmao, but often when I do workouts etc I have to arrange my playlists manually to not have them be the same all the time, but I still need my marker songs for the start/end for example.