signum_ignitum

Pretty simple. Every time someone searches a term on your website, this plugin tracks it.
It also tells you (roughly) where they’re searching from. Note that the plugin does not log searches from logged in users, so you can search your own site without polluting the logs.
Quis scrutatur ipsos scrutatores?

Search Log

Keeps a log of what people search for on your site.

mattsgarage

The search functionality in woocommerce doesn’t search by sku by default.
This simple plugin adds this functionality search facility of your site, in both the public site and admin panel
Just install and activate – no config required.
Tested with Woocommerce 1.5.6, 2.0.7, 2.0.18, 2.2.4, 2.2.10, 3.4.4, 4.0.1 and 4.2.0
See the <a href="http://www.mattyl.co.uk/2012/12/11/woocommerce-plugin-to-search-products-by-sku/" title="accompanying blog post" rel="nofollow ugc">Accompanying blog post</a> for more information.

Search by SKU for Woocommerce

Extend the search functionality of woocommerce to include searching of sku

Search Log vs Search by SKU for Woocommerce