unfriend-multiple
Unfriend multiple friends on Facebook, using a checkbox
I just needed this and made this simple code, for now I just paste it into the console and use it, maybe I'll make it an extension later; to use it now just paste the code on the console, select those who you want to unfriend, and click the button "Bye!" that will show up above!
one of the benefits I get from this is practicing setTimeout() since it makes the browser freeze if you don't use it.. good experience :)