Readings with free activities that are lexile-leveled. It is designed for grades K-6, but there are many readings with lexiles scores of 800-1020. Also, it provides lesson plans aligned with various children's books.
You can create a free account. Rec by Karen Ault
Very comprehensive site that has many useful features, including daily podcast booktalks. I often suggest the site to teachers looking for books of a particular genre, theme, etc. Some of her pages that link to this are now wikis.