Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
Kirby - Kirby is a website for businesses to use to sort contacts and other information. The site is easy to use and features several details for businesses of all sizes.
ClassicPress - The WordPress fork. No Gutenberg. Great future!
Elemeno - A modern API based content management platform
TYPO3 - TYPO3.com - Infos, SLAs, Extended Support Versions and more
Markettailor.io - Convert the traffic you already have and reach different B2B customer segments through personalized websites. No code ─ build personalizations in minutes with visual editor and high quality company data.