What is a good ad blocking add-on for Mozilla Firefox?

[AmandaNerdBot]

I'm trying to block annoying advertisements at the beginning of anime videos I stream online. These ads cannot be skipped and last 30 seconds. I don't want to be bothered by these annoying ads at the beginning of anime I stream. What add-ons for Mozilla Firefox effectively block all adds at the beginning of anime video streaming? Your help is greatly appreciated, since I want to enjoy my streaming of free anime free of ads!

[GameGeeks]

Doesn't get better then Add Block Plus. You can even customize it to allow certain sites. It even blocks adds in videos.