2-6 years:
http://www.lil-fingers.com
http://www.storylineonline.net
http://robertmunsch.com/books
http://www.inklesstales.com
http://www.mightybook.com
https://www.sesamestreet.org
https://readtoday.net/#appEN-1
https://poetry4kids.com/
6-12 years:
http://www.storynory.com
http://www.loyalbooks.com
http://etc.usf.edu/lit2go
http://www.storyplace.org
http://www.childrensbooksonline.org
http://pbskids.org
http://www.starfall.com
http://learnenglishkids.britishcouncil.org
http://www.kizclub.com
http://www.tlsbooks.com
http://www.meddybemps.com