The tiniest of spoilers for Baldur’s Gate: Descent to Avernus below (but I swear this is a CoS question).

Currently I’m a player in Descent to Avernus, but I’m one of the primary DMs for my group. In a recent session we were in the Elfsong tavern in Baldur’s Gate and the ghost began singing her song. The DM had found someone who recorded themself performing the song and put it on YouTube so he was able to actually play the song for us. It was very cool and I gave him huge props for that.

My question is, does anyone know of anything available to augment the play of Curse of Strahd that is along these lines? I know that there and some letters and pages from Strahd’s diary in the adventure book, but anything else? Anyone with experience running the adventure that has used a certain prop or add-on to good effect?