You can try searching for graded readers online. There’s quite a few free resources avaliable, like those on this list. You can also try the content on Satori Reader.
My personal favorite option is to join a book club here on the forums. The Absolute Beginner’s Book Club is about to start reading レンタルおにいちゃん in just a week, take a look at the book’s home thread if you’re interested.