Radek Mezulanik

You can lock whole website by setting it under maintenance.
Features:
<ul>
<li>
Select roles who applies maintenance mode
</li>
<li>
Set a redirect to login page
</li>
<li>
Edit a maintenance message in wysiwyg editor including media
</li>
</ul>
<h3>Sponsorship</h3>
<a href="https://www.productboard.com" rel="nofollow ugc">Productboard</a>

Zedna Maintenance Mode

Set you website under maintenance to lock content while development.

irenem

A simple tool that allows you to switch between user accounts without the hassle of logging in/out. It allows you to view, review and do what yours does to your site.
<h4>Features</h4>
<ul>
<li>
Switch between user account and to guest user.
</li>
<li>
Inherit all capabilities of the selected account, as if you are that very same user.
</li>
<li>
Helpful for developers, designers, and site owners.
</li>
</ul>

User Switcher

This plugin helps me very much when I need to test custom user roles.

I like it

This is really helpful plugin for testing my user's issue with my site. When I have only admin account I can easily switch to a random users and reproduce their issue. Thanks for the great solution.

Perfect tool for testing users issue

A helper tool to help you switch between user account without logging in and out.

Zedna Maintenance Mode vs User Switcher