Multiplication.com (tons of games): http://www.multiplication.com/games/addition-games
Fun Brain: http://www.funbrain.com/brain/MathBrain/MathBrain.html
PBS_Cyber Chase: http://pbskids.org/cyberchase/math-games/
Hooda Math: http://www.hoodamath.com/games/
Minecraft Maths: http://www.mathematicshed.com/mister-teach-minecraft-maths.html
Cool Maths: https://www.coolmath4kids.com
Math Play: http://www.math-play.com
Maths games: https://mathsframe.co.uk/en/resources/category/22/most-popular
Math Antics: https://mathantics.com
Math Games: https://au.mathgames.com
Number Rock: https://www.youtube.com/c/NUMBEROCKLLC/playlists