Microsoft Family Safety: This is a free parental control software that is included with Windows 10. It allows you to monitor your child's activity, set screen time limits, and restrict access to certain websites and apps.

Qustodio: Qustodio offers a free version of their parental control software that allows you to monitor your child's online activity, block inappropriate content, and set screen time limits.

Kaspersky Safe Kids: Kaspersky Safe Kids is a free parental control program that allows you to monitor your child's online activity, block inappropriate content, and set screen time limits.

Norton Family: Norton Family offers a free version of their parental control software that allows you to monitor your child's online activity, block inappropriate content, and set screen time limits.

OpenDNS Family Shield: OpenDNS Family Shield is a free service that allows you to set up custom DNS settings to block inappropriate content at the router level, which can help protect all devices on your home network.

Please note that while these programs are free, they may have limitations on features or the number of devices that can be monitored. Additionally, some of these programs may offer premium features for a fee.