anttti

When creating new posts or pages (of regular WordPress types or custom post types), this plugin makes them private by default.
Just activate the plugin, no further configuration is necessary (or even possible).
This plugin is a fork of the <a href="https://wordpress.org/plugins/private-post-by-default/" rel="ugc">Private Posts by Default plugin</a> since it didn’t work properly in WordPress 4.3 and wasn’t updated in more than three years.
<h4>Important URL’s</h4>
<ul>
<li><a href="http://rarelyneeded.com/" rel="nofollow ugc">Author’s Blog</a></li>
<li><a href="http://twitter.com/anttti" rel="nofollow ugc">Twitter</a></li>
</ul>

Private by Default

When creating new posts or pages (of regular WordPress types or custom post types), this plugin makes them private by default.

shazdeh

The WordPress Database Reset plugin allows you to reset the database back to its default settings without having to delete the site and recreate it.
Useful tool for theme and plugin developers who often have to clean up the mess and start over.

WPMU Database Reset

Clean up a single site in a WP network, by removing all posts, comments, terms and media files. A clean slate for the site.

Private by Default vs WPMU Database Reset