TwinklThis is more for printouts, and usually at a fee, but they are offering a month of free access to parents in the event of school closures. (March-April)
Phonics PlayThis website usually has a fee but they are offering free access during this time.
Teach Your Monster To Read This is free for all users on the website and the app is currently free to download. This website covers everything from letters and sounds to reading full sentences.