Suggested search tools for SharePoint On-Prem 2019

We're using SharePoint On-Prem 2019, and are looking for a good search tool that can bring back results from a contact list.  The contact list includes look-up reference to other lists.  We had Bamboo search on our SharePoint 2010 site, but they don't offer a version that is for On-Prem.  Any good suggestions on recommended search alternatives?  Thanks!