I was looking for something just like this two weeks ago and came up empty due to Google being filled with just the huge frameworks like bootstrap or with SEO listicles with no content. It's disappointing how hard it can be to find stuff like this. (I guess "classless" is the keyword I wasn't aware of.)
Anyway, I'm confused about what makes something a CSS 'framework'. I feel like I just want decent defaults more than a framework, and that seems to be what this basically comes down to. Is there anything else to it?
You can have a look at https://github.com/troxler/awesome-css-frameworks which is an extensive collection of CSS frameworks. Check out the "Class-less" section for similar projects.
There is also an open PR to add Simple.css to the list: https://github.com/troxler/awesome-css-frameworks/pull/85