THE adblocker.
anything else is either a fork of it, or worse than it.

Excelente bloqueador de anúncio! Com ele, o firefox vira outra coisa, bem melhor que navegadores concorrentes com bloqueadores nativos rsrsrs

Ok gasss

Absolutely fantastic tool. It's not limited to ads (though it handles them wonderfully), if play around with the element picker a bit you can easily remove a good chunk of the cruft that corporations seem to love plastering on their products these days. Get good at writing the filters by hand and you can do /magical/ things. I love the feeling of not being subject to every whim of some marketing executive. Take control over your experience on the internet! It's fun!

Tip for new users: though the defaults are very good, make sure to check the "Filter Lists" tab in the dashboard and see if there is anything else you'd like to enable- I recommend some of the "Annoyances" lists.

I literally don't know how other people tolerate the web without uBO. It is possibly the best extension ever made.
No matter if you are just someone looking to block ads or if you are a privacy-security enthusiast wanting to personally regulate every single network request, you will find that uBlock Origin suits your needs.
If you find that ads and trackers make the Web intolerable, and wish it wasn't- install uBO.

Simply the best

The dev are doing God's works