Google Custom Search - Google Custom Search enables you to create a search engine for your website, your blog, or a collection of websites.
Sooqr - Sooqr Search provides relevant and innovative site search engine for the website.
Klevu - Klevu offers instant site search solution for eCommerce stores.
Swiftype Site Search - Swiftype Site Search helps to sell more, get the right answer to more people on the platform and surface relevant content for readers and followers.
Findify - Personalized eCommerce tool
SLI Systems - SLI Systems