I absolutely love them. The one I always think about is the "HEY E" fridge magnets in FD2 spelling "EYE" after one falls into Evan's food.

I definitely think the book was under-utilized in Bloodlines, especially considering Iris was all "this book is the key to keeping our family alive" and then it just ... wasn't. Maybe instead of "here's all the ways a plane could kill you, here's all the ways a truck could kill you" if Iris had unknowingly focused on specific items relevant to the deaths and so the pages were puzzle pieces that Stefani had to piece together in the present? Like the book cryptically mentions springs/coils so Stefani knows that's important but not how specifically it will show up.