Azure Cognitive Search - Azure Search makes it easy to add powerful and sophisticated search capabilities to your website or...
Ninfex - Experimental people-powered search engine
ElasticSearch - Elasticsearch is an open source, distributed, RESTful search engine.
Wakie - Get Instant phone advice from peers
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.
DelegateCall - Fully blockchain-based Q&A site