I found that W3Schools have pretty cool CSS templates that works great with Sitecore.
So if you are trying to do a quick demo for clients or just playing around with your environment. Head over there and check it out.
Here is the link
https://www.w3schools.com/w3css/w3css_templates.asp
I will upload the video on how I used Shelley Benhoff’s course to build a whole site with one of this and build different components.