TED-Ed (Lessons Worth Sharing) is a website that is great for educational purposes. You can find riddles, short educational videos, etc.

Can you solve the wizard standoff riddle?
Can you solve the buried treasure riddle?
Can you solve the frog riddle?
Can you solve the temple riddle?
Can you solve the dark coin riddle?
Can you solve the seven planets riddle?
Can you solve the fish riddle?
Can you solve the locker riddle?
Can you solve the airplane riddle?
Can you solve the three gods riddle?
Can you solve the river crossing riddle?
Can you solve the virus riddle?
Can you solve the pirate riddle?
Can you solve the prisoner boxes riddle?
Can you solve “Einstein’s Riddle”?
Can you solve the prisoner hat riddle?
Can you solve the egg drop riddle?
Can you solve the control room riddle?
Can you solve the passcode riddle?
Can you solve the bridge riddle?
Can you solve the rebel supplies riddle?
Can you solve the Leonardo da Vinci riddle?
Can you solve the false positive riddle?
Can you solve the penniless pilgrim riddle?
Can you solve the giant cat army riddle?

There are are other websites that list interesting videos for kids.

The Kid Should See This