aviket

This Plugin searches all the posts, pages with a blog. You have to enclose the term you want to search 
with shortcode like [findwordsc]Searchterm[/findwordsc]. The plugin “Searchterm” is searched throughout the blog. A rolling carousel is displayed 
which contains button links to all the posts and pages, containing the word “Searchterm”. 
After clicking the link, the post is displayed in a modal popup(Thickbox). In the post thus displayed by clicking on the link, all the occurrences of search 
terms are highlighted. The highlighting style is controlled by settings. 
The settings page is opened by clicking in the “Findwords options” menu item in the settings menu. 
mark.js Javascript/ Jquery plugin is used for highlighting. 
Link to the mark.js plugin: 
https://markjs.io

Findwords

This Plugin searches all the posts, pages with a blog. You have to enclose the term you want to search

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

Findwords vs Search by SKU for Woocommerce