Title says it all. For the commander party for duskmourn there were these little room cards that you could use to build a haunted house akin to betrayal at house on the hill. No one else at my LGS really wanted them, and I have copies of every single one, except vivarium.

A little more info about them. https://www.reddit.com/r/MTGRumors/s/Q6M0t9Nvzh