You can also look up for these other topics: Framework Coding Standards Boilerplate CMS Tool Security Hacktoberfest
Modern, Crazy Fast, Ridiculously Easy and Amazingly Powerful Flat-File CMS powered by PHP, Markdown, Twig, and Symfony
Pagekit CMS
Hybrid Content Management System with the freedom of a headless CMS and with the full functionality of a traditional CMS
Share content between your websites.
Graby helps you extract article content from web pages
Contentify is an esports CMS based on the PHP framework Laravel
A fork of https://bitbucket.org/fivefilters/php-readability
MaxSite CMS
Grav Admin Plugin
Really flexible headless CMS, built on top of Symfony and GraphQL.