Now personally I've been playing for a while and find some serious love for the hidden bits and pieces they hide in their models and their fluff, some are so blatant that I think that most if not all are purposeful. So I'm gonna compile a list of these bits that I've found, post some more if you can find any, It's really quite fun.
Let's start with the obvious,
Sue - Obvious Johnny Cash reference
Gremlin power (Deliverance) - Gotta be a shout out to the classic bayou hick horror
Bete Noir - Her name is a slight variation of the French slang for pet peeve.
The Honey Pot- The name of the casino and brothel in book 4, is an interesting one, Honey Pot is Japanese slang for a certain female reproductive organ, fitting for a brothel.
Run 19 (fluff in book 2) - Has a lot of similarities to Flight 19 the disappearance of pilots on a routine training drill.
This one is a bit long-
Coppelius ability (unexplained connection) - This says that Coppelius can be hired by Hoffman, this is because Coppelius is the original name of the sand man, who is a book written by an author who's last name happens to be Hoffman is described as stealing the eyes of children and feeding them to his children on the moon, hence the abilities (remove eye) and (The Crescent Moon)
If anyone has any more I would love to hear em, I think I'm forgetting a few but best of luck to ya! Happy fluff hunting!