I've been a book designer for 10+ years. For longer than that I’ve had a secret mental checklist of things I wanted to include if I ever got to do my own book. Things like an infographic panel on the back cover.
Here are some of the things I managed to get into my first book...

A cold open - the story starts straight away (well, on page three)

(I've wanted to do this since May 22, 2019) https://twitter.com/jackdraws/status/1131156298085687296

A double-spread title page (surprisingly controversial)

A song you can actually play

A wordsearch with secret easter egg answers (privitisation, corporate, profiteering etc)

A typographic reference to a childhood fave

A built-in flipbook

A Trumpian book cover (Ms Fortune also installs a gold lift that goes up to her office)

Digital-native visual language - expressions rendered as emoji, maps as Google maps

A dig at celebrity authors

A poem

(The poem background reuses the morbid wallpaper I made for Great Expectations) https://twitter.com/jackdraws/status/1197919558008475649

A proper credits page