Meet Wagtail, an open-source Django content management system built by Torchbox. It's free, beautiful, versatile and fast. Find out how to get started.
Directus.io - The Headless CMS + Backend for Every Custom Build
Directus is an open-source Headless CMS with the flexibility and power of a Data API. It allows managing both content and raw data, in any new or existing SQL database — keeping all your data pure, organized and portable, end-to-end.
Strapi is the next-gen headless CMS, open-source, javascript, enabling content-rich experiences to be created, managed and exposed to any digital device.