Fiction, nonfiction, sci-fi, history, lowbrow comic books, hardcore philosophical treatises, poetry, plays, funny stuff, sad stuff, weird stuff, stuff you can't remember if you've read already but it looks enticing so you might as well order it from your favorite indie bookstore (or use bookshop.org if you don't have one). The only constant is that all of these (or at least one of their editions) are two hundred pages or fewer.