Sumit Singh

Easily hide your WordPress site from public viewing by requiring visitors to log in first. As simple as flipping a switch.
Make your website private until it’s ready to share publicly, or keep it private for members only.
Features
<ul>
<li>WordPress Multisite compatible.</li>
<li>Specific page redirects visitors back to the url they tried to visit without login.</li>
<li>Extensive Developer API (hooks & filters).</li>
<li>Customizable. Set a specific URL to always redirect to on login.</li>
<li>Filter exceptions for certain pages or posts.</li>
<li>Restrict REST API to authenticated users.</li>
<li>Translation Ready & WPML certified.</li>
</ul>

Visitor force login page

Easily hide your WordPress site from public viewing by requiring visitors to redirect specific or login page in first.

sunnyverma1984

Increase user registration on blog by making post or page available only for registered user. 
This plugin allows to make post, page or partial content visible to registered users only. You can hide partial content using shortcode <code>[RegUserOnly][/RegUserOnly]</code>. Or you can hide complete post or page by selecting Visibility to <code>Registered Users</code> in post/page editor.
<h4>Plugin Features</h4>
<ul>
<li>Easy installation and integration</li>
<li>Custom tinymce shortcode button</li>
<li>Cross Browser capability</li>
<li>Translation ready</li>
</ul>

Only for Registered Users

Make post, page or partial content visible to registered users only

Visitor force login page vs Only for Registered Users