A while ago, @nbeck0212 found the resource Ehon navi, which allowed you to read all kinds of graded readers, ranging from books for babies to readers for teenagers. It currently asks for a small subscription fee, but compared to buying a book, it’s much more doable. It’s not really a book per se, but it’s a handy resource. (Full credits to @nbeck0212 of course)
EDIT: Wait woops, I think you’re specifically asking for non-graded readers. Full credit goes to me for being very bad at reading.