ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
DocFetcher - DocFetcher is a portable German/English open source desktop search application.
Xapian - Xapian is an open source probabilistic information retrieval library, released under the GNU...
Advanced Recent Access - Advanced Recent Access is designed to see more properties of your recent used resources (files and directories). Key features: can see more properties of the recent resources, such as path, size, type, date modified and date created. And more.
Algolia - Algolia's Search API makes it easy to deliver a great search experience in your apps & websites. Algolia Search provides hosted full-text, numerical, faceted and geolocalized search.
Recoll - Recoll is a desktop full-text search tool. Recoll finds keywords inside documents as well as file names.