Have you tried Tumblebooks yet? You can get your hands of a large collection of free interactive ebooks through your library membership. The collection is best for young and learner readers and contains many well-known picture book and junior chapter book titles (even some non-fiction too!). The books are animated with pictures and sounds, and you even have the option of reading the book yourself, or having it read to you. As well as English, there are titles in French, Spanish, Chinese, Russian, Korean and German, which is perfect for those that are learning another language.
Prefer comics? Tumblebooks has those too! Geronimo Stilton, Archie, Nancy Drew, Max Finder Mysteries and more.