The best extension for Firefox.

uBlock ist super keine probleme.

great

The best. I highly recommend reading the documentation, and consider using "Advanced Mode" afterwards, if you're willing to learn how. (I use the "Medium level," personally, and have had great success (this will make sense if you read the documentation.)

If you don't want to bother with doing that, no worries! You get perfectly adequate protection even without enabling Advanced mode!