Okamoto Hidetaka

This plugin gives you Related Item Widget and function.
If you want to show Related Item List, you can do following actions:
<ul>
<li>Add <code>Elasticommerce Related Widgets</code> in your widgets area.</li>
<li>Add <code>escr_related_item();</code> function in your theme or plugins.</li>
<li>If you only want to get the data, you can use <code>escr_get_related_item();</code> function.</li>
</ul>
Notice 
This plugin requires WooCommerce Plugin , so please install it. If WooCommerce Plugin is not installed or activated, this plugin will not work.
Required 
This Plugin cannot use Elasticsearch version 2.x. Please use Elasticsearch version 1.5 instead.

Elasticommerce Related Items

You can get good Related Item List powered by Elasticsearch.

horike

Add much extensions and power-up WooCommerce.
We adopted the Elasticsearch to search engine. You can also search, such as a custom field by replacing the WordPress of standard search function. The accuracy of the product search feature dramatically improves in WooCommerce.
<h4>Contributors</h4>
<ul>
<li><a href="https://profiles.wordpress.org/horike" rel="nofollow ugc">Horike Takahiro</a></li>
<li><a href="https://profiles.wordpress.org/hideokamoto" rel="nofollow ugc">Hide Okamoto</a></li>
</ul>
<h4>Suport WP-CLI</h4>
Set up Elasticsearch below. wp elasticsearch setup –host=example.com –port=9200

Elasticommerce Search Form

This plugin is that WooComerce product search replace WordPress DB with Elasticsearch.

Elasticommerce Related Items vs Elasticommerce Search Form