Privacy Badger is a browser plugin that blocks ads and trackers. Keep in mind that it is not a ad blocker explicitly. It does help protect your privacy from known sources that tend to be invasive. Privacy Badger also helps block various 3rd party means of fingerprinting your browser to track you as well as blocking scripts attempting to do the same.
From project site:
Privacy Badger is a browser add-on that stops advertisers and other third-party trackers from secretly tracking where you go and what pages you look at on the web. If an advertiser seems to be tracking you across multiple websites without your permission, Privacy Badger automatically blocks that advertiser from loading any more content in your browser. To the advertiser, it’s like you suddenly disappeared.
Note: Some users have reported that the plugin can degrade web browsing experience. If you encounter this be sure to look at future 100DPO posts with other options we’ll cover.