These bookmarklet and exploits can be downloaded as a .html file and ran. This has the advantage of avoiding the prying eyes of teachers as when downloaded and ran, your teachers can't see the file you're running.
An IFrame loader to load Proxy sites your teacher can't see
A History flooder
An inspect element clone known as Eruda
An ad blocking bookmarklet
A snake game
A Tab cloak, you can use this as a bookmarklet, you won't need it for this ;)
CrownJS
tri.js which makes your webpages 3d
piano.js to load a piano on webpages if that's your thing
FULL CREDITS ARE IN THE FILE PAGE