Awesome Awesome Awesome!!! This is exactly what I was looking for! I often lose large amounts of time in YouTube, and I while I have blacklisted it before I constantly have to go back for school related purposes.
I've tried blocking elements with U-Block with little success...
Then I found this Add-On! It is customizable and blocks all elements that you could want blocked, and is easy enough to toggle on and off. It's working great!