In this challenge I've included all the books on some of the more interesting challenges I have published (both personal favourites and ones that scored well on the site). Needless to say, many duplicates had to be removed (not that there's anything wrong with that). The source lists (see below) emphasise classics, modern literary fiction, novellas, drama and philosophical non-fiction.
Goodreads Most Influential Books Under 100 Pages
Goodreads "World's Greatest Novellas"
Goodreads Must Read Classics: 2020/21 Update
The Drama 100 - A Ranking of the Greatest Plays of All Time
Koen Book Distributors' Top 100 Books of the Past Century
500+ Doubly Acclaimed Works of Fiction
50 Classic Novellas
Greaterbooks.com: Prehistory to 700 A.D.
Greatest Books Top 500 - September 2020 Update
Note: This challenge is 'rigged' in my favour in the sense that I have used the above lists extensively to choose books to read.