1. https://materializecss.com
2. https://getuikit.com/
3. https://semantic-ui.com/
4. https://foundation.zurb.com/
5. https://bulma.io/
6. http://getskeleton.com/
7. https://purecss.io/
8. https://groundworkcss.github.io/
9. https://cardinalcss.com/
10. https://github.com/powertoweb/powertocss
and many others