Check out PineGrow (Offline) and Webflow (Partly data-driven) too, it's quite impressive what they can do. I've built a site builder 5 years ago for a client u

Check out PineGrow (Offline) and Webflow (Partly data-driven) too, it's quite impressive what they can do. I've built a site builder 5 years ago for a client using Semantic UI, it was a great choice for data-driven sites but hard for custom sites (which pinegrow and webflow are more suited for). Many site-builders these days grow their own framework to ensure a lock-in effect, you can't move the site off the platform because it takes too much work to re-bind the data and functionality (Especially eCommerce).