ClearOS 7 no longer offers blacklist rules by default. The idea of this list being manually maintained by a network admin is not likely to play out in your favor and hence ClearOS offers blacklisting as a subscription based service. however there are those that would prefer to manage the content filter rules.
A1 Computers offers our copy of content filtering rules ready for ClearOS. Click to Download
If you intend to use this list, double check the items filtered as they not be the preferred setting in your network environment.