Lamb Agency

This plugin adds a simple dropdown menu to the admin pages for developers and clients to understand, at a glance, what environment they’re currently viewing.

Enviromon

Select and save your current environment.

drupalmatts

This plugin will allow you to secure your development, staging and UAT environments 
with an http authentication block that can be controlled in admin but also turned 
off via a declared variable in your config file. It allows you to bring your Database 
back to non-production environments without having to physically turn off the plugin each time.
Variable: <code>define('WP_SHIELD_UN', '');</code>
This simple line of code (recommended to add to a file ignored by your code management 
software and required into your wp_config.php file) will override the enabled flag 
if the plugin’s settings. Enable in production and add the above code. If that 
require file doesn’t exist in your other environments, it will prompt users for the 
set username and password.

WP Shield

This plugin will allow you to secure your development, staging and UAT environments with an http authentication block that can be controlled in admin  …

Enviromon vs WP Shield