One of my personal favorite examples is Seth Dickinson, who wrote some of the lore for Destiny, including the Book of Sorrow and Marasenna in-game lore books, which are IMO some of the best parts of the universe.
He then went on to write The Traitor Baru Cormorant, which I enjoyed a lot, and more recently Exordia - which is amusingly similar in themes and specific plot elements to the Book of Sorrow and really feels like Seth went "wait I wasn't done with that yet".
He then went on to write The Traitor Baru Cormorant, which I enjoyed a lot, and more recently Exordia - which is amusingly similar in themes and specific plot elements to the Book of Sorrow and really feels like Seth went "wait I wasn't done with that yet".