I love all the easter eggs in "Good Omens" by Terry Pratchett and Neil Gaiman, in both the book and the TV-series. I especially like the mentions of all the interesting books. I'd love to read more of them and I'll start out with the books from season 2 in the show. This challenge is open, with no beginning and no end, and I'd love to get suggestions about all the books I've missed, so I can add them.