elapseit - Resource planning, time-tracking & invoicing for SMBs
Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
WordPress - WordPress is web software you can use to create a beautiful website or blog. We like to say that WordPress is both free and priceless at the same time.
ClassicPress - The WordPress fork. No Gutenberg. Great future!
Craft CMS - Content management system built on Yii PHP Framework
TYPO3 - TYPO3.com - Infos, SLAs, Extended Support Versions and more