Thing is, the book in the show is very likely to be something totally different. Theres an entire Dark Arts wing down there behind the locked gate that contains Starswirls scrolls. Im pretty sure that Twilight said there were hundreds of time manipulation spells in there alone.
As for running out of ideas, FIM is a world in itself, with magic. Rather like Discworld. Thats up to 37 books alone, etc
Thing is, the book in the show is very likely to be something totally different. Theres an entire Da