Mindshare Labs, Inc.

<p>A highly customizable AJAX-based WordPress search bar alternative with the ability to autocomplete <a href="http://en.wikipedia.org/wiki/Faceted_search" rel="nofollow ugc">faceted search queries</a>. Users can quickly and dynamically browse through your site’s taxonomies and post metadata to find exactly what they’re looking for, and results can be loaded beneath the search bar instantly.</p>
<h4>Features</h4>
<ul>
<li>Searches post title and body content</li>
<li>Can search by multiple keywords, and by full phrases</li>
<li>Highlights search terms in results</li>
<li>Option to send search queries as events to your Google Analytics account</li>
<li>Facets by post category</li>
<li>Can search in multiple categories (OR or AND search)</li>
<li>Category options are dynamically generated and autocompleted as you type</li>
<li>Attractive and lightweight interface based on jQuery, Backbone.js, and the VisualSearch.js library</li>
<li>Customizable results template using standard WordPress functions</li>
<li>Search through an unlimited number of user-specified taxonomies and meta fields (including data contained in Advanced Custom Fields).</li>
<li>Conduct radius searches against data stored in the ACF Map field (i.e. search for posts within x km of a user-specified location).</li>
</ul>


WP Ultimate Search

Powerful AJAX-based search alternative which supports faceting queries by taxonomies, terms, location, and post metadata.

Md Aminur Islam

PluginizeLab

<p>The Metadata Viewer plugin displays post, user (ie. posts, pages, and custom post types, user, WooCommerce products & orders) meta keys and their values at the bottom of the post & user editing page. There is also integrated realtime search feature.<br />
Just install a single plugin to solve multiple purpose like to show posts, pages, custom post types & user meta.</p>
<h4>Features</h4>
<ul>
<li>Posts Metadata Viewer</li>
<li>Custom Post Types Metadata Viewer</li>
<li>Pages Metadata Viewer</li>
<li>Users Metadata Viewer</li>
<li>WooCommerce Products Metadata Viewer</li>
<li>WooCommerce Orders Metadata Viewer</li>
</ul>
<h4>Up-Comming Features</h4>
<ul>
<li>Comment Metadata Viewer</li>
<li>Term Metadata Viewer</li>
</ul>


Metadata Viewer

A plugin or theme developer can view metadata by this plugin easily.

WP Ultimate Search vs Metadata Viewer