Mario Peshev

Delete all Custom Field entries assigned to posts that do not exist in the posts table.
Navigate to Settings -> Remove Unused CFs and delete all postmeta for non-existing posts.

DX Remove Unused Custom Fields

Does exactly what it says.
Installed, navigate to the settings page, click "Delete" and Done! Cannot be easier than that.
Thank you!



Simply Awesome!

Delete the Custom Fields from your postmeta table where assigned posts no longer exist.

WPExplorer

Post Types Unlimited is an easy way to add custom post types and custom taxonomies to your WordPress site (the right way). The plugin works with any theme and is easily translatable. With Post Types Unlimited you can:
<ul>
<li>Create custom post types.</li>
<li>Create custom taxonomies.</li>
</ul>
Post Types Unlimited makes use of core WordPress functionality for the admin screens and post type, taxonomy registration. This means the plugin is fast, slim and uses the familiar WordPress UI.
Additionally you won’t find any upsell or advertisements in the plugin because there isn’t a “Pro” version. It’s the perfect plugin for adding post types and/or taxonomies to any site (including your client sites) without worrying about extra bloat or annoying ads.
The design of your post types and taxonomies created with the Post Types Unlimited plugin are controlled by your theme. The plugin doesn’t do any hacking or advanced modifications to your templates and thus works great with ANY theme.
If you are using our amazing <a href="https://totalwptheme.com/" rel="nofollow ugc">Total WordPress Theme</a> you will have access to many extra settings that will give you full control over the display of your post types and taxonomies.
This plugin doesn’t have any upsells, banners or other marketing strategies. This makes it perfect for use with any site, including client websites.

Post Types Unlimited

Create unlimited custom post types and custom taxonomies.

DX Remove Unused Custom Fields vs Post Types Unlimited