CurrentWare BrowseControl - BrowseControl web filtering software blocks websites based on URLs and categories. Policies can be customized for each user, department, or OU. Includes other features such as an app blocker, port filter, and download/upload blocker.
Surge for Mac - Advanced Web Debugging Proxy for Mac & iOS
Qustodio - Free parental control software. Monitor and track your child's online activity. Block dangerous sites and protect kids from online bullying.
Charles Proxy - HTTP proxy / HTTP monitor / Reverse Proxy
NxFilter - Best performance. You don't want to slow down your network by installing a network security software. NxFilter is a light-weight DNS filter. It doesn't cause any latency issue in your network.
HTTP Headers - HTTP Headers allows you to quickly see the HTTP header information for the current URL.