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.

Ron Zvagelsky

Monthly grid view calendar widget highlighting archived and/or future posts.
Additional Features:
<ul>
<li>Popup details for each date with posts</li>
<li>Optional details include post author and comment count.</li>
<li>Ability to show posts by post type, category, specific taxonomy and/or term</li>
</ul>
<a href="http://presshive.com/plugins/wordpress-blog-post-calendar-plugin" rel="nofollow ugc">For more information or to request additional features, please visit the plugin page</a>

Blog Post Calendar Widget

The Blog Posts Calendar Widget allows you to display your archived or future posts in a calendar as a sidebar widget.

DX Remove Unused Custom Fields vs Blog Post Calendar Widget