vinodvaswani

This plugin will give you ability to add related products of your choice in bulk. and you can also get the all related products of any product.
features include:
<ul>
<li>Add woocommerce related products in bulk. eg. select 5 related products form left side and select 2 products in right side, in results 5 selected related products will be 
related for each product in right side.</li>
<li>Select product category wise.</li>
<li>get all related products of any product.</li>
<li>Remove related product from any product.</li>
</ul>
NOTE: Woocommerce must be installed in you website.

WC Bulk Custom Add Related Products

This plugin will give you ability to add related products of your choice in bulk. and you can also get the all related products of any product.

mshirk

This Plugin makes it easy to add WooCommerce “Related Products” to individual blog posts. 
Select any of your WooCommerce Products from the WordPress “Add Post” admin screen to add them to the bottom of your post content. Inserts the selected products with linked thumbnails to the bottom of your post content and includes css classes that make them easy to customize! This plugin is not meant to be an all encompassing WooCommerce Related Products Add-On. It is just a simple solution to get WooCommerce products onto your blog posts

WooCommerce Simple Add Related Products to Blog Posts

This Plugin makes it easy to add WooCommerce "Related Products" to single blog posts.

WC Bulk Custom Add Related Products vs WooCommerce Simple Add Related Products to Blog Posts