Mecabricks is a Lego building software like LeoCAD or Lego Digital Designer but online. If you want to make models and save them, I recommend creating an account, but Mecabricks does not require an account. It has an in-built animation and rendering feature too.
Cursors.io is a puzzle game where you have to solve mazes,avoid dangers and draw!(I have no idea what the drawing is for.)
Fight other flowers for garden authority.
Agar.io is a game where you are a cell on the map of a petri dish.You can play as Guest but you have limited features and your progress will not be saved.
This is a science game which teaches you about physics,You can create your own levels too.
This is a game where you have to feed the monkeys the food they are supposed to eat(I would recommend reading the instructions first).
https://www.nms.ac.uk/includes/games/monkeybusiness/index.html
This doodle may be a bit frustrating but it is really fun.
This is an adventure game where you have to figure out what caused a power outage.You have limited time!
This is a BBC site for kids on History. It also has games.
http://www.bbc.co.uk/history/forkids/
This is a science game that teaches you about atoms, protons etc.
https://testtubegames.com/bondbreaker3.html