As far as I know, this is a complete list of every book Emma Watson has mentioned or been pictured with. I also included authors that she's mentioned.
https://www.emmawatson-updates.com/p/those-are-not-necessarily-emmas.html?m=1
https://instagram.com/oursharedshelf?igshid=YTQwZjQ0NmI0OA==
https://instagram.com/emmawatson?igshid=YTQwZjQ0NmI0OA==
https://ew.com/books/2017/02/21/emma-watson-book-recommendations/
https://ibelieveinbookfairies.com/2017/03/emma-watson-talks-about-the-book-fairies-with-entertainment-weekly/