starblank

This free plugin shows next and previous product in single product view in same category.
Installation
Simply upload the .zip file into wordpress, then activate the plugin. A new submenu called Next/Previous Product will on Woocommerce Options left bar. 
This plugin requires Woocommerce in order to run. 
Has been tested with the new Storefront Woocommerce theme and is fully compatible with DIVI framework.
How to use
–Free Version allows: 
Show the previous and next product on the single product view of your store, from the same category, on the top the page.
—<a href="http://starblank.com/en/next-previous-products-for-woocommerce-premium/" rel="nofollow ugc">Premium Version allows:</a> 
-You can choose the location of the next /previos product links: 
 * Over the product 
 * At the bottom of the page 
 * Over the product description 
 * Below product description 
 * Floating in both sides of the screen
-Choose what product will be seen: 
 * Show only products from same subcategory 
 * From same category 
 * Show random products
<ul>
<li>
Show the image and/or the title of the product, all fully customizable in color and size
</li>
<li>
Allows you to use custom arrows instead of default ones
</li>
<li>
and much more!
</li>
</ul>
<a href="http://starblank.com/en/next-previous-products-for-woocommerce-premium/" rel="nofollow ugc">You can get the premium version here</a>
Have fun!

Next / Previous Product for Woocommerce FREE version

This free plugin shows next and previous product in single product view in same category. Installation Simply upload the .

flynsarmy

Adds a widget that can displays subcategories of a given category (or top level). Has options to show/hide post counts, exclude categories, depth limits and/or empty subcategories.

Flynsarmy Subcategory List Widget

Adds a widget that can displays subcategories of a given category (or top level).

Next / Previous Product for Woocommerce FREE version vs Flynsarmy Subcategory List Widget