OKAY OKAY HERE ARE SOME
Drift Boss at Math Playground. Math Playground has a couple fun games
MathIsFun has a bunch of games like powerline.io. (Wasn’t blocked at my old school)
Jenxys Games. HAS SUBWAY SURFERS AND STUFF. Teachers haven’t found out lol
Tetris! Might be blocked but there are so many versions on different sites it won’t be blocked. The one I play is on github.io or something
Snake, like the google game. Doesn’t work in all schools but does sometimes.
Hope this helps!