Los Angeles University has free over 1800 children's eBooks in English that you can download or read online.
Η collection contains classic books such as Cinderella and The Wizard of Oz, as well as poetry, educational and fantasy ebooks. You can read them online or download them in a wide variety of formats, including EPUB, Kindle, PDF, and more.
On her website UCLA (university of Los Angeles) you will find books published from 1728 to 1999. The newer books are probably the minority. The oldest of them even contain illustrations on wood. All the books we tested (from the oldest ones) had easy-to-read text in a format image, although some were a bit dark.
Books can be sorted by title, publication date and author. Can you do search using themes, year, collection or creator. THE default display are thumbnails but you can also view them as a list.
Books are printable in PDF format, although the pages will vary in size. See the online library from here (UCLA collection of children's books)