Vitalii

This plugin can to quickly switch user by click. It is comfortable for develop themes and plugins.
After load page, loading neat closed sidebar from right. By click on arrow it show or hide sidebar. Sidebar is 
displaying all registered WordPress users. By click on user is ajax send user ID to back end where switch user. 
After response is JavaScript reload page with registered new user.
<h3>Why using iBryl Switch User?</h3>
<ol>
<li>Quickly switches user by click.</li>
<li>Doesn’t slow down loading.</li>
</ol>

Plugin Name: iBryl Switch User

This plugin can to quickly switch user by click. It is comfortable for develop themes and plugins.

Fugu Design

One-click maintenance mode
This plugin adds a button to the admin bar for toggling the builtin maintenance mode.
Core maintenance mode
A .maintenance file is generated and copied to the WordPress installation folder when turning on the maintenance mode. 
A maintenance.php file is generated and added to the wp-content folder for custom HTML code.
Your custom maintenance page will also be active during the core, plugins and themes updates.
<h4>Special Features</h4>
<ul>
<li>
set which roles can switch the maintenance mode
</li>
<li>
set which roles can bypass the maintenance mode on the frontend
</li>
<li>
set the entire HTML code used for the maintenance page
</li>
<li>
preview the maintenance page before saving
</li>
<li>
enable the theme file support, so you can create in each your themes a maintenance.php file to customize the maintenance page
</li>
<li>
restore all default settings
</li>
<li>
restore default HTML code
</li>
<li>
create/delete the maintenance file in the active WP theme
</li>
</ul>
<h3>Translations</h3>
<ul>
<li>English – default, always included</li>
<li>French</li>
</ul>

Maintenance Switch

Customize easily and switch in one-click to (native) maintenance mode from your backend or frontend.

Plugin Name: iBryl Switch User vs Maintenance Switch