Jabawack

Simple Custom Posts per Page (SCPP) allows to configure the number of posts displayed for every custom post registered in WordPress.
See <a href="https://wordpress.org/extend/plugins/simple-custom-posts-per-page/screenshots/" rel="ugc">Screenshots</a> to known why it is called “Simple”.
In your Readme page in Setting tab of WordPress, it adds an option for every post type.
Disable Plugin in Template: 
You can disable plugin filters in your template whenever you want. Maybe you need a query with a different number of custom posts per page for a specific post type. 
Using this code before your query, the filter plugin will be disabled for a specific post type:
<pre><code><?php $GLOBALS['ado_cspp_disable']="YOUR_TYPE"; ?>
</code></pre>
With this code, you can use your personalized query for your loop.
More: 
You can find more informations in the official <a href="http://www.adostudio.it/blog/simple-custom-posts-per-page-397/" rel="nofollow ugc">Post</a> on my Blog.

Simple Custom Posts per Page

This plugin allows to configure the number of posts displayed for every custom post registered.

Toro_Unit (Hiroshi Urabe)

Simple Customization posts per page for your sites.
You can change posts per page by taxonomy or category or tag or custom post type.
<h4>Available Setting</h4>
<ul>
<li>Custom Post Type</li>
<li>Custom Taxonomy</li>
<li>Category</li>
<li>Tag</li>
</ul>
This plugin use <code>pre_get_posts</code>.
<a href="https://github.com/torounit/pppp" rel="nofollow ugc">This Plugin published on GitHub.</a>
Donation: Please send Amazon Gift to donate[at]torounit.com.
<h4>Translators</h4>
<ul>
<li>Japanese(ja) – <a href="https://www.torounit.com/" rel="nofollow ugc">Toro_Unit</a></li>
</ul>

Powerful Posts Per Page (PPPP)

Posts per page for custom post types and taxonomies.

Simple Custom Posts per Page vs Powerful Posts Per Page (PPPP)