PhilHilton

Adds shortcode for including a custom field on a page or post. 
Create a custom field on your post/page. Then use the following shortcode to include it on your site:
[embed_custom_field “field-name-here”]
This is useful for arbitrary bits of text or code that you don’t want the WYSIWYG editor to mangle and reformat.
This may work fine with versions older than 3.9.0 (and almost certainly does) but it has not been tested.
<ul>
<li>Note that the Gutenberg blocks content editor includes a “Custom HTML” block type, which negates the need for this plugin. It will NOT be maintained after December 31st, 2019.</li>
</ul>

Embed Custom Field

Adds shortcode for including a custom field on a page or post. Note that the Gutenberg blocks content editor includes a "Custom HTML" block  …

hwinote

HwiNote Content Search Tool helps site administrators and developers find where text, shortcode snippets, widget content, and custom field values are used in a WordPress site.
Main features:
<ul>
<li>Search posts, pages, and public custom post types.</li>
<li>Search custom fields.</li>
<li>Search widget settings and content.</li>
<li>View shortcode usage.</li>
<li>Highlight matching text in the editor when opening a result.</li>
<li>Supports OR, AND, exact match, and regular expression modes.</li>
</ul>
This plugin is designed for site maintenance, migration checks, and content audits from the WordPress admin area.
<h3>Related Links</h3>
<ul>
<li>Japanese Introduction 
https://hwinotes.com/plugin-content-search-tool/</li>
</ul>

HwiNote Content Search Tool

Search posts, pages, custom fields, widgets, and shortcode usage from the WordPress admin.

Embed Custom Field vs HwiNote Content Search Tool