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.

Andrew Norcross

tripflex

<p>Creates a panel to change or delete meta keys in bulk. Useful for when you are switching plugins or themes that use specific meta keys for functionality, or for general cleanup for older sites that may have older meta data that is no longer in use.</p>


Post Meta Manager

A simple utility plugin for changing or deleting post or user meta (custom fields) keys in bulk.

WP Ultimate Search vs Post Meta Manager