Creative Commons
Classroom Clipart
ARKive
Free Clipart
Pixabay
Encyclopedia Britannica
World Book Online Encyclopedia
Pebble Go
PebbleGoNext
CultureGrams
Newsela
BrainPop & BrainPopJr
Enchanted Learning
Time for Kids
National Geographic Kids
Discovery Kids
Incompetech - Music, etc.
Royalty Free Music
Royalty Free Sound Effects
Musopen - Public Domain Music