It's good to use multiple privacy protection extensions as they complement each other's abilities. Ghostery and DuckDuckGo Privacy Essentials both provide features for blocking third-party cookies and trackers, while Privacy Badger detects and blocks additional potential trackers. So, using both Ghostery and Privacy Badger will give you an extra layer of protection.
However, since Ghostery and DuckDuckGo Privacy Essentials have similar functionality, it might be redundant to use both of them together. In this case, you could choose to use one or the other. Ultimately, it's essential to find the combination of extensions that works best for you and provides the level of privacy protection that you are comfortable with.