Damian Gostomski

<p>The Imposter plugin allows site administrators to take on the role of another user. This is useful for development and testing purposes, as well as the ability to troubleshoot user issues without needing the user password.</p>
<p>It will add a link for each user in the users list, which will log the administrator as that user. They’re then logged in as that user and are no longer an administrator, until they logout of the user session, at which point they’re logged back in as themselves.</p>


Imposter

Allows administrators to take on the role of another user for development, testing and troubleshooting purposes without knowing the users password.

Gulzar Ahmed

<p>Only logged-in users can view the frontend or backend if this plugin is activated. The password reset process on wp-login keeps on working.</p>
<ul>
<li>No options/settings</li>
<li>No by-pass</li>
</ul>
<h3>Compatibility</h3>
<ul>
<li>WooCommerce</li>
</ul>
<h3>Usage as MU-Plugin</h3>
<p>This plugin is very simple and can also be used as a must-use plugin. That way no admin of a website can deactivate the plugin, making sure the requirement of just authenticated  users is ensured.<br />
! No automatic updates are made for mu plugins</p>


WP Logged-in Only Basic

A Plugin to lock down the whole site to prevent public access.

Imposter vs WP Logged-in Only Basic