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.

Andrew Norcross

tripflex

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.

Post Meta Manager

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

WP-Admin Search Post Meta vs Post Meta Manager