I have this sudden belief about writing a story. Would you actually include conceptional works, ideas, and versions of a franchise before its final version, like Valkyria Chronicles, Arknights, Girls' Frontline, etc.
Like I had this idea about using conceptional stuff from a franchise's artbook like characters, vehicles, clothing appearance, etc, and then rewriting it to serve as an extra thing in a fanfic that you are writing for a specific franchise.
Take Valkyria Chronicles for example, there's a bunch of preproduction stuff like characters that I may or not decide to use it. Because, no one bothers.