TYPO3 Alternatives for PHP

Joomla is a free and open-source content management system written in PHP. The CMS is built entirely by volunteers from all over the world and has a strong community that provide educational resources, and extensions. 

PyroCMS is a free and open-source Content Management System written in PHP on top the web development framework Laravel.

October is a free, open-source and self-hosted content management system written in PHP on top of the framework Laravel. The CMS features a universal extendable dashboard, inspector, reusable CMS components and a plugin system that can be used to extend functinality of your website. The plugin store contains thousands of community-made plugins that can either be purchased or installed for free. As a data store, October CMS supports MySQL, PostgreSQL and SQLite.

Drupal is a free and open-source CMS written in PHP. Drupal is used for creating website for businesses, political parties and governments. The CMS currently powers 2% of all websites on the internet.

Craft CMS is a flexible, user-friendly CMS for creating custom digital experiences on the web and beyond. Craft is designed from the ground up to empoer the entire creative process. From the user-friendly interface to the completely customizable back end, everything you interact with is designed to just make sense. With Craft your content comes first. No more trying to make your content work within the confines of the CMS.

Backdrop is a full-featured content management system written in PHP. The Backdrop CMS allows non-technical users to manage a wide variety of content. It can be used to create all kinds of websites including blogs, image galleries, social networks, intranets, and more.

Exponent CMS is a notable free and open source content management system that contains its own independent modular software framework of enterprise level.

Quanta is a free, open source Content Management Framework thought for programmers and used for the creation of new-generation websites and applications.

Fork CMS is a free and open-source, easy to use content management system built with PHP and Symfony Components. The content management system features an intuitive administration panel that makes it easy to create and manage content for the web. Fork CMS also comes packed with apps that can be installed to extend the feature set of the content management system.

Bear CMS is a self-hosted content management system that seamlessly integrates with your website. With Bear CMS you own your data and content, which is store on your own server. Your websites and Bear CMS's management tools integrate seamlessly and creates an experience that content managers and editors will enjoy.

WonderCMS is the smallest flat file content management system. The CMS is built with PHP and has been developed since 2008. No initial configuration required to setup the WonderCMS, the installation is straight forward and simply requires you to unzip and upload 5 files.All data within WonderCMS is structured as JSON format and the flat file nature of the content management system also allow you to migrate hosts easily by transfering files across, no database migration required.