An Introduction - but it looks the same as body text, so there doesn't seem to be a good reason to use it.

There is a pretty big gap underneath it, which doesn't disappear if it's left blank, but some may think it is less conspicuous.

This is the Body section. You can put all the usual text here if you wish, but an advantage of using the Page Builder sections instead is that there you can create a Contents block of jump-links ('waypoints') at the top of the page which offers a way to navigate to each segment.

Featured row - Blue background

A full-text block, so you can write what you like. Note that the included items don't bring the whole of their listing content (ie picture and text) into this particular type of Featured row.

Featured row - Transparent background

Another free-text block, but without the blue background. You can write what you like.

On this one, the full listing content (ie picture and listing text) is shown with the featured item(s).