Hulbee Enterprise Search - Hulbee Enterprise Search is another powerful site search solution that intelligently retrieves information and documents regardless of their source or location.
SearchSpring - SearchSpring is an eCommerce site search tool.
CommVault - Commvault is a site search platform that helps legal or compliance officers and corresponding end users to explore and retrieve files and email across different applications, storage devices and computers.
SearchBlox - SearchBlox is an out-of-the-box Enterprise Search Solution built on top of Apache Lucene/Solr.
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
Datafari - Datafari is a leading open-source enterprise search engine that was released under the Apache License with the multitude of connectors.