The website below has lots of books that the children can read online, and also some activity ideas.
Teach your monster to read
Once you have made an account, your child can practise their phonics and reading by playing different games.
Free ebook library
Scroll the bottom of the page where it says browse by Oxford level and chose the book band your child is on, or the level underneath that one of you think that they need harder books. Your child's home reader should have a coloured sticker on the spine and that will tell you what colour band they are on. You will need to sign up for a free account to read the books.