Time for brainstorming!  These are all categories we have used in the past for bingo squares or the substitution list: 

*Book in a Series
*Author you've neverread before
*Book older then you are
*Fairy Tale or Fairy Tale Retelling
*Graphic novel or Comic
*Pet or Animal Companion
*A main character over the age of 30
*LGBTQ+
*Multiple POVS
*Under 100 Pages
*Romance Plot or Sub-plot
*Translated
*Humour
*Non- fiction
*Thriller or Suspense
*With a Blue Cover
*POC Author
*Horror or Paranormal
*Colour in the Title
*Seasonal Read
*Book from your TBR
*Crime or Mystery
*Sci-fi or Fantasy
*Banned Book
*Book made into a film or tv series
*Historical (fiction or non-fiction)
*Number in title
*Female author
*Three word title
*Craft, Hobby or Cookbook
*Written by an author from your state or country
*Person's name in title
*Book with a woman protagonist
*Animal on the cover
*More than 300 pages
*Disability or Mental health
*Recommended
*Read a book from the year you were born
*e-book or Audiobook
*Mythology
*Title begins with first letter of your name
*Dystopian
*Book mentioned in another book
*Diverse reads
*One word title
*Movie/TV Tie-in
*Award Winning/Bestseller
*Disabled Author
*Non-western Setting
*Set in your state/country
*Title is at Least Five Words Long
*YA/Childern's
*Anthology/Collection
*non-human POV/ main character
*indigenous author
*Set somewhere you've been
*Has illustrations (but not a comic or graphic novel)
*Checked out from the library
*Set at a school/university
*Biography or memoir
*No sex/romance
*Re-read

If you have other ideas please comment on this post!  If not I will create the 2025 from these options.