WordPress - WordPress is web software you can use to create a beautiful website or blog. We like to say that WordPress is both free and priceless at the same time.

Progress Sitefinity - Sitefinity's web content management software is a marketing command center to drive growth for your business. Easily manage multi-site experiences deployed your way.

ApostropheCMS - Apostrophe is a powerful website builder platform built on an enterprise open source CMS, offering in-context live editing, visual design tools, and multisite enablement in a full stack JS environment.

Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.

Drupal - Drupal - the leading open-source CMS for ambitious digital experiences that reach your audience across multiple channels. Because we all have different needs, Drupal allows you to create a unique space in a world of cookie-cutter solutions.

ClassicPress - The WordPress fork. No Gutenberg. Great future!