https://www.achieve3000.com/
Achieve 3000 provides differentiated, nonfiction reading passages with associated comprehension activities. The reading passages are catered to your student's instructional level and they are highly engaging articles that cover a wide variety of topics that include and are not limited to current events and student interests. 

https://www.readworks.org/
Readworks is another online reading program that offers differentiated reading passages that includes a variety of genres that are included within fiction and nonfiction texts. The reading passages can be selected by your students current reading level and there is a comprehension activity that follows the reading passage. 

https://tarheelreader.org/
Tar Heel Reader is a collection of free, easy-to-read, and accessible books on a wide range of topics. Each book can be speech enabled and accessed using multiple interfaces, including touch screens. I will posting is under writing as well because it can allow you to write your own book, as well.