Automattic

Daniel Bachhuber

A quick and easy way to see post meta associated with any given post. When activated, this plugin prints your post meta keys and values inside of a post meta box.
Originally developed for <a href="http://vip.wordpress.com/" rel="nofollow ugc">WordPress.com VIP</a>-hosted clients, we thought it would be useful for development environments, etc. too. Feel free to <a href="https://github.com/Automattic/Post-Meta-Inspector" rel="nofollow ugc">fork the plugin in Github</a> and pull requests are always welcome. Hit us with feedback, questions, bug reports, and feature requests in the forums.

Post Meta Inspector

Lovely little tool. Saves having to go into the database and look through the postmeta table when debugging. Thanks!

Really useful

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.

Post Meta Inspector vs WP-Admin Search Post Meta