I agree with you Anna, web content filtering is important and has a multitude of benefits for both individual users and organizations. It helps protect minors from inappropriate content, reduces malware infections, protects against exploit kits, increases staff productivity, gives efficiency in network bandwidth, and minimizes the company's liability.
My favorite one is "Pumpic Internet Filter", This content filtering application has a variety of features. It can effectively block websites according to age presets. Pumpic also uses multiple strategies for filtering. These include white-listing, black-listing, and blocking of obscene words from the website copy. In addition to Internet content filtering, this application also performs child parental control. It can perform geo-fencing, check the child's location, control the child's smart device remotely, and even view all logs of SMS and calls. This application does not charge a fee and is compatible with the Android platform.