I know it's here, on CurseForge... I can't remember the name to save my life. I remember it was a book that had a narrator's voice, and allowed you to add your own pages with various texts and sound files to narrate those said pages and you could collect pages through chests in dungeons, etc. The last time I remember using it is in 1.10 I believe but I know it's been updated to at least 1.11. The narrator said something like this as an example page when opening the book -
"Welcome to the I don't remember this part mod, which allows you to add narrative subjects into this book and make a sort of adventure novel in which you can collect pages for as you continue your journey through your game, I hope you enjoyed this example"?