There are lots of things that I use proxies to access on my school Chromebook, but I'd like to share somethings that work on mine that might work on yours.
Pacman (just search it in google and it should be unblocked)
16personalities.com (Ik its not the accurate test but its cool its on my chromebook.)
The proxy I use is resources.manoahinvest.com (you could also use platform.manoahinvest.com but its slower.)
Comment anything else you can use!