Social Studies
National Geographic Kids - grades K-6
EconEdLink - Online PD for teachers and economics lessons and collections for grade K-12.
iCivics - Put your students into action with these games and lessons. - grades 7-12
Engaging Congress - Free civics/government primary source-based interactive that is intended for distance learning. It can be used on the web or downloaded as an app from Google Play or Apple Store. - grades 7-12