ProcessWire is a great, light-weight, easy-to-use PHP-based content management system. It's lesser known than Drupal and WordPress and definitely doesn't get the recognition it deserves, but it's a great alternative to these technologies. In my opinion, it's easier to use than both, and offers more flexibility than WordPress for custom content types, and is generally much simpler to theme for compared to Drupal. ProcessWire is quite mature, having been around for almost 2 decades, and is a great choice for my clients who want to update the content on their website.
ProcessWire
Below are some projects that use ProcessWire.
See all the other Technologies I work with.