brendaegeland

A common web design pattern is to have a primary navigation with the top level pages, and then a separate 
navigation element on each page that shows only those pages related to a common top-most page. This widget helps 
to build those secondary navigation elements.
If your page structure was like this:
<ul>
<li>Home</li>
<li>About</li>
<li>— Our History</li>
<li>— Our Staff</li>
<li>— — Employment Opportunities</li>
<li>Services</li>
<li>— Widget Development</li>
<li>— Gadget Deployment</li>
<li>Contact Us</li>
</ul>
and you added the widget with its default settings to a sidebar, it would create a list like this:
<ul>
<li>About</li>
<li>Our History</li>
<li>Our Staff</li>
<li>— Employment Opportunities</li>
</ul>
on any of the pages in the About subtree. Notice that the top-most ancestor, About, is included as the first element of the list.
<h4>Options</h4>
<ol>
<li>Title. The widget title. If left blank, it defaults to the title of the top ancestor page.</li>
<li>Show Title. Maybe you don’t want a title. Just turn it off here.</li>
<li>Top Page. You can select one of your pages to be the top page, or you can choose Default, which determines the top-most ancestor of the page being displayed.</li>
<li>Menu Class. Gets applied to the outermost <ul> element.</li>
<li>Before Links. HTML to be inserted before links in the list.</li>
<li>After Links. HTML to be inserted after links in the list.</li>
</ol>

Subpages in Context

Lists pages and subpages for a given page, or the top ancestor of the current page and all of the ancestor's descendants

macnetic-labs

NF Subpages adds pages and fieldset elements to the ‘Layout’ Elements’ block. It also includes labels and custom classes for elements to allow for more interesting layouts and styling. Subpages works only with javascript, otherwise it displays the pages with fieldsets.
This plugin requires the Ninja Forms plugin.

NF Subpages

NF Subpages adds pages and fieldset elements.

Subpages in Context vs NF Subpages