Oxford Owl is a fantastic free online resource that gives access to an amazing range of children's books on a phone, tablet or PC. Once set up, you can filter your options by your child's age, book band colour or reading series. This is an excellent option if your child wants to vary their reading throughout the week alongside their home readers which are changed on a Monday and Friday.
There is also a lot of guidance and some instructional videos on how to support your child in using phonics to decode words in their reading.