FiboSearch - Give your WooCommerce users a fast, convenient and relevant autocomplete search and save them the effort
WebshopLogic WP Google Search - Free plugin for integrating Google Custom Search box into your WordPress website without coding.
Advanced Woo Search - Advanced Woo Search - WordPress ajax search plugin for WooCommerce store. Search in product title, description, excerpt, sku, tags, categories, attributes, custom fields, custom taxonomies.
Relevanssi - Relevanssi replaces the standard WordPress search with a better search engine, with lots of features and configurable options.
Ajax Search Lite - WordPress Live Search plugin - Ajax search lite. A responsive live search engine for WordPress, for free.
Ivory Search - Ivory Search is a WordPress search plugin that improves WordPress Search by providing advanced options to extend search or exclude specific content from search.