A novel approach
During a game of Dungeons & Dragons, I had a spur-of-the-moment idea to create a fake book based on one of the characters as a joke.
Based on pulp novels and 80s B-Movies, the cover was a success, however it just made me want to make more and for each of the other party members.
Another request was something akin to the Deck of Many Things, which is an in-game relic, however it caught my attention as a parable to the real-life counterpart - The Tarot Deck.
With this I could do one for each of the party, but also a lot more based on story choices and decisions made thus far in the campaign.