Matej Kravjar

Plugin adds section to post edit page in WordPress admin, where the post metadata are displayed in convenient table with the option to export the data into JSON format

Post Meta View and Export

This plugin adds possibility to view and export post metadata for superadmins.

Yong

Javier Esteban

This plugin is useful if you want to see all post metas that stored in a post or page and the value of each meta. 
Whether for debugging, quick view a data or just curious what is saved inside your post or page meta.
Just install and activate, Post Meta Viewer plugin will show a metabox contain the list table of all post metas that saved for each post or page in easily readable format.
No settings needed just plug and play.
<h4>Thanks to Contributors</h4>
Thank you for the contibution to this plugin to
<ul>
<li><a href="https://profiles.wordpress.org/nobnob/" rel="nofollow ugc">Javier Esteban</a> for translating this plugin to Spanish</li>
</ul>

Post Meta Viewer

View all post meta that saved in a post, page or custom post type in easily readable format. No settings needed just plug and play.

Post Meta View and Export vs Post Meta Viewer