Louis

This WordPress plugin extends the default search to include meta (custom) fields
Major features in WP Search Include Meta Fields include:
<ul>
<li>No configuration necessary</li>
<li>Integrates with core search functionality</li>
<li>Doesn’t alter the database</li>
</ul>

WP Search Include Meta Fields

License: GPLv2 or later WordPress plugin to extend default search to include meta fields

bellathemes

This plugin is meant to used by some of themes by Bellathemes. This plugin registers required custom post types and meta fields to make theme able to work.
Note: Some of the features are not available on free version of the theme.
This plugin creates sub menu ‘Bella Kit’ on wordpress admin panel under settings. Enable ‘Custom post types’ according to your requirement.

Bella Kit

Register common custom post types, taxonomies and meta fields.

WP Search Include Meta Fields vs Bella Kit