1. A distributed open-source database with a flexible data model for documents, graphs, and key-values.

  2. Redis is an open source in-memory data structure project implementing a distributed, in-memory key-value database with optional durability.

  3. Meet Neo4j: The graph database platform powering today's mission-critical enterprise applications, including artificial intelligence, fraud detection and recommendations.

  4. OrientDB - The World's First Distributed Multi-Model NoSQL Database with a Graph Database Engine.

  5. MongoDB (from "humongous") is a scalable, high-performance, open source NoSQL database.

    open-source

  6. HTTP + JSON document database with Map Reduce views and peer-based replication

  7. Open-source graph database.

  8. Document-Oriented NoSQL Database

  9. High-performance, distributed memory object caching system

  10. Built like a hedge fund.

  11. FlockDB is a distributed graph database for storing adjancency lists, with goals of supporting high rate of add/update/remove operations.

  12. NoSQL JSON database for rapid, iterative app development.