https://addons.mozilla.org/en-US/fir...cker-ultimate/
I also use an add-on called "Disconnect":
https://addons.mozilla.org/en-US/fir...on/disconnect/
And if you
really want to block content unless you authorize it, there is "NoScript".
https://addons.mozilla.org/en-US/fir...ddon/noscript/
Although, NoScript is quite aggressive and you will probably find that many of the features of your favorite websites will no longer work unless you actively whitelist them.