Free Content Management Software
GeniXCMS
GeniXCMS is a Simple and Lightweight CMS and Framework. It's PHP Based CMS. Free and Opensource.
Subrion
Subrion is a PHP/MySQL based CMS & framework that allows you to build websites for any purpose. Yes, from blog to corporate mega portal.
Flextype
Flextype is super fast headless content management system with an elegant architecture and built-in smart cache.
Agility CMS
Agility CMS is a cloud-based content management system for building and managing responsive websites and apps.
LightCMS
Easily Create Fantastic Websites with Highly Customizable Templates & Intuitive Tools for...
Mixcore CMS
Mixcore CMS is an Open Source Enterprise ASP.NET Core / Dotnet Core CMS for building amazing digital experiences. It's made by a dedicated community. Anyone can use it, and it will always be free.
CouchCMS
With no knowledge of PHP required at all you can make any static web-page editable by your clients.
SilverStripe
Silverstripe CMS is designed to be simple to learn and easy to use. Whether updating a page or publishing multiple pages on a large scale site. Give access to edit only specific areas of your site. Architected to safeguard your data from malicious activity or data-loss, even while scaling up complex sites.