Do you really want to bring fan fiction into this?
50 Shades of Grey Trilogy started as fan fiction for Twilight. However, the universe was changed to one of E.L.James's creation by removing all Bella, Edward, and Cullen references.

Several novels have been published recently that are outside the fan fiction overhang.
Let's try the end of Robert Jordan's Wheel of Time series, which Brandon Sanderson kindly finished for fans after Jordan's demise.
Let's try notes from a book that Robert Heinlein perhaps might have written that Spider Robinson created in his honor and memory.
Let's also try all the rewrites of classics: Android Karenina, Sense and Sensibility with Sea Serpents - I think there are more but I didn't see them in the short search: http://benhwinters.com/books/

We have rules. But creativity will get you around the rules once you understand the reason for them and the spirit behind them.