dainius.kaupaitis

When navigating on pages widget shows links to child pages. If there are no child pages – widget shows „brother“ pages. 
Link of currently viewed page can be styled through CSS. Widget shows nothing if user is browsing Posts (not Pages). 
Admin can configure:
<ul>
<li>widget title</li>
<li>which pages must be excluded</li>
</ul>
Widget can be localized.

DKA Child pages widget

adaldesign

If you are looking for a simple way to index the content of a long WordPress page or post, this plugin is your ticket.
Just like the “Content” quick-links on the right of every WordPress.org Codex page, this widget will automatically create a list of links to each header in the content of the pages you wish to index. You don’t need to create any anchor links for this to work.
By default, it also includes an on-page search form so that users can easily find anything on the page that is indexed.
The plugin is extremely light, unobtrusive and easy to use. It will only show up on sidebars of pages in which you use the [SIPC_Content] shortcode. This plugin will load jquery on pages that use the shortcode if you theme doesn’t already.
<a href="http://test.adalclients.wpengine.com/sipc-demo/" title="Click here for a live demo." rel="nofollow ugc">See a live demo here</a>
<h4>Suggested Uses</h4>
<ul>
<li>Create simple FAQ pages without complex use of Custom Post Types.</li>
<li>Make your long posts easier to reference.</li>
<li>Leave a review to tell me how YOU used this plugin.</li>
</ul>
<h4>Languages</h4>
Available in Spanish and Serbian.

Search & Index Page Content

Provides a sidebar widget that indexes and links to the headers in the content of any page/post and allows users to perform on-page search.

DKA Child pages widget vs Search & Index Page Content