ACF Pro Addon

The Flexible content field acts as a blank canvas to which you can add an unlimited number of layouts with full control over the order.

Similar to the repeater field, this field contains sub fields. However, instead of 1 set of sub fields, the flexible content field allows you to create an infinite set of sub field groups (called layouts). With these layouts predefined, you can then add them into your field when ever you want and where ever you want.

Technically, you could set up a flexible content field with every layout that appears on your website (basic paragraph, contact form, file link, images, etc) and add it to a field group that appears on all pages. Then when creating a page, you wouldn’t need to specify a page template, but just add the relevant content blocks (layouts) onto the page. Then the whole website would run off page.php!!