A few of the pictures shown in Harley's Museum of Memories come from Batman: The Animated Series (1992).
The picture of Harley's family in her Museum of Memories resembles the cast of Married... With Children.
This delving into Harley's inner psyche bears the influence of Charlie Kaufman. Indeed, two of his films are name-checked in the episode, Being John Malkovich (1999) and Eternal Sunshine of the Spotless Mind (2004).
In her memory museum, Harley's family looks a lot like the family from "Married with Children" AND Katey Sagal who played Peg Bundy on that show also played Kaley Cuoco's mother on 8 Simple Rules.