Phoenix Online

This easy-to-use plugin allows you to quickly and easily edit post meta values for almost any post type (including custom post types)
Edit post meta as plain text, in textareas, as light-weight HTML or using the full WordPress WYSIWYG editor!
From the first version, this has been designed for ease of use by site Contributors and Editors, but keeps settings reserved for Admin’s only. This gives site Adaministrators control over what less-privileged users can bulk edit.

Bulk Postmeta Editor

This plugin makes it easy to check and edit serialized data in a targeted and comfortable way. Both custom fields and hidden meta data can be easily queried by post type. The plugin then lists all data in an editable input field of your choice which makes comparing and editing the data a breeze.  


Very helpful for debugging

Allows you to bulk-edit post meta information (including custom post types) from a single place.

meloniq

Enhance the default WordPress admin search by including custom fields (post meta) in search results. 
This plugin seamlessly extends the post listing (edit.php) search functionality, allowing administrators to quickly find content based on values stored in custom fields.
It works out of the box with no configuration required—just activate and start searching. 
Especially useful for sites that rely heavily on custom fields, such as those built with ACF or other meta-based data structures.
Lightweight, efficient, and fully integrated with the native WordPress admin experience.

WP-Admin Search Post Meta

Search WordPress admin posts by custom fields (post meta) directly from the default search.

Bulk Postmeta Editor vs WP-Admin Search Post Meta