YAM is an open-source, privacy-focused website manager. You create a list of allowed websites, and this extension will block access to all pages that are not in that list.
The list is synchronized through Chrome to all of your devices, so you can log into Chrome with your child's account, add or modify entries in the list and they will synchronize in near real-time to a child's computer.
You can also choose to block all content from other sites, but this requires a more complex configuration since many pages require content from other sites to operate correctly.
Need help? Send me an email or open an issue on Github: https://github.com/sarangak/yam-allowlist-manager