Lavalite - PHP CMS built with Laravel and Bootstrap.
Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
DEV.to - Where software engineers connect, build their resumes, and grow.
Anchor CMS - Free and lightweight blogging system
Gila CMS - An on-in-one solution for the digital business
Textpattern - Textpattern is an elegant content management system that is free, open source software.