Mike Bricknell-Barlow

<p>This plugin allows you to take manual control over the products that are shown under the Related Products section on WooCommerce single product pages. When editing a product, it’s possible to pick up to 4 products which will be shown in the Related Products section. Choosing less than 4, or not choosing any, will show the default selection of related products according to woocommerce rules to fill the 4 slots.</p>
<h3>Settings</h3>
<p>None – no configuration required.</p>


Manual Related Products for WooCommerce

Allows you to choose a manual set of products for display under the Related Products section on WooCommerce single product pages.

Marcin Pietrzak

<p>Display cool, animated fly-out or fade box with related content.</p>
<p>When a reader scrolls to the bottom of a single post, page, or custom post type, an animate box will be shown allowing the reader to select the previous or random available post or posts in the selected configuration:</p>
<ol>
<li>Just previous</li>
<li>Previous in category</li>
<li>Previous in tag</li>
<li>Random</li>
<li>Related using YARPP (only post/pages)</li>
</ol>


upPrev

Great plugin. Works great, lightweight and doesn't take a lot of resources to manage. 

Great Plugin

Display cool, animated fly-out or fade box with related content.

Manual Related Products for WooCommerce vs upPrev