The Divi Builder is one of the first page builders. It is integrated with the Divi and Extra themes or available as a stand-alone plugin. Divi added a Theme Builder component late 2019 which provides the ability to create the full range of theme templates, including headers and footers.
Divi appeals to designers and frequently releases free templates, including theme templates, so that it is easy to find ones that works with a wide variety of niches. While Divi is a general purpose theme, Extra is a magazine style theme that has some additional features, such as a rating module and archive builder.