My recomended site was Kokorono-ehon (Children’s Picture Book).
I think it is difficult to attract children interest by no pictures, that is why I chose picture book.
In this site there are a lot of pictures. In addition to that, these stories are transferred from Japanese to English. So, if you wanted to read this in Japanese, you clicked “日本語”.
And on top of that, I think this is also useful for teachers and parents, because this is separated by expected effects. For example, to be kind means blue, and to be honest is pink one. So, teacher can select some stories to accordance with their aim of class.
However, there are two weak points in this site. One is that there are no pronunciation system, and the other is this translation is not every sentences are suitable.