Starfall
https://www.starfall.com/h/
Storyboard That
https://www.storyboardthat.com/
Wordle
http://www.wordle.net/
ABCYa!
https://www.abcya.com/
Book Adventure
https://bookadventure.com/
Read Write Think (in conjunction with the National Reading Association)
http://www.readwritethink.org/
ReadWorks
https://www.readworks.org
K12 Reader
https://www.k12reader.com
Storyline Online
https://www.storylineonline.net
Brain Pop
https://www.brainpop.com
Super Teacher Worksheets
https://www.superteacherworksheets.com
Enchanted Learning
https://www.enchantedlearning.com/
Education City
https://www.educationcity.com/us/free-resources/
Spelling City
https://www.spellingcity.com/
Epic!
https://www.getepic.com/
Vooks
https://www.vooks.com/resources