Here is a recently-discovered Civics website, with some excellent resources, as well as lesson plans and interactive games. https://www.icivics.org/
About the website: iCivics is a non-profit organization dedicated to reinvigorating civic learning through interactive and engaging learning resources. It was founded by former Supreme Court Justice Sandra Day O’Connor. You can read more about the organization here: https://www.icivics.org/our-story
Thanks to Holly Williams for this contribution.