Oxygen is a WordPress plugin that includes a page builder and theme template builder.
Oxygen
Oxygen is a somewhat unique combination of theme template builder and page builder that takes over and replaces the theme. The template building features have support for ACF, Meta Box, and Toolset. Of all of the plugins in the builder class, Oxygen is one of the most developer focused and includes a code block for custom PHP and a PHP callback function for working with advanced field types. It has a loop builder and Gutenberg block builder.I created a post showing how to create single and archive templates using Oxygen, if you are interested in it.
Pros: The template building features work well and are easy to use. Oxygen is actively developed, has a very active Facebook community, and good documentation. The builder is very flexible and it is possible to include custom fields in archive templates. Oxygen is GPL licensed.Oxygen has a visual conditional display feature as well as a programmer API for creating your own conditions.Version 4 was recently released with speed and other editor enhancements.Of all of the builders considered here, Oxygen is known for outputting straight HTML without a lot of the extra DIV elements that other builders use to support animations and more elaborate designs. Sites created with Oxygen generally score well on the various speed tests.
Cons: Requires more knowledge of HTML, CSS, and JavaScript than other page builders. Uses shortcodes when creating content. There is no roadmap and bugs can take a long time to be addressed.
Additional Information: Working with Oxygen is different than working with a theme and some builder / themer plugin. Toolset support is not as good as the options custom field options.