https://privacybadger.org/ Automatically blocks trackers (not relying on black lists or similar).
https://addons.mozilla.org/en-US/firefox/addon/multi-account-containers/ This allows you to separate different websites and services to different containers, minimizing the tracking they can do with cookies, it also helps if you want to use multiple accounts on same website at the same time. A bit more info on this.
https://noscript.net/getit - Choose which domains a website can run javascript from. This one is a bit more involved and takes some time to learn to use, it quite often breaks websites since they like to load javascript from dozens of different domains, so can't really recommend it to everyone but if you can stand using it you'll get a lot more control over what happens on your browser.
Also remember that you can also install uBlock and quite a few other addons on Firefox Mobile (ad-free youtube on the go!).
Also remember that you can also install uBlock and quite a few other addons on Firefox Mobile (ad-free youtube on the go!).