I'm starting work on some musically-themed Slaanesh, having been struck by how similar the Daemon Prince's pose looks to how my old conductor used to stand right before a piece started, combined of course with the fact that Slaanesh has the Infernal Enrapturess.
So I built the Daemon Prince a podium and stand (pictures are before priming, will upload part 2 once I've painted) as well as a booklet with his score (unfortunately I don't have enough fine control to paint the scores onto the page, but we can imagine that for now).
I also "improved" a base with toothpicks for the Infernal Enrapturessess, making her look like she's on some sort of stage (I hope?).
Camera quality is terrible because I'm using a cheap phone. I'll borrow a friend's the next time I bring this army out, hopefully for a good picture of the complete army. CC welcome for anything other than the camera.
Unfortunately, I don't have any ideas on how to theme any other units beyond these two, so any suggestions and/or feedback on that front would be greatly appreciated.