AboZain Albanna

Rename Default Post is a simple plugin gives you the ability to Rename your Default Post label to custom name in admin menu. 
Why would I leave my client a menu item that says ?Posts? when they are adding news updates, or portfolio items, 
 So you can simply use this plugin.
<h3>For Example Change Posts to News</h3>
How the plugin works: = 
Go to Settings -> Rename default post.

Rename default post Labels

Awesome

A simple, lightweight WordPress plugin Rename your Default Post labels to custom name in admin menu

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.

Rename default post Labels vs WPMU Database Reset