Tetrisly - Starter kit for design systems and wireframes builder (Sketch/Figma)
Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
Framer - 🔥 Design real websites right on the canvas.
ClassicPress - The WordPress fork. No Gutenberg. Great future!
Flawwwless ui - Simplified open source React.js components library 🚀
TYPO3 - TYPO3.com - Infos, SLAs, Extended Support Versions and more