neo4j - Meet Neo4j: The graph database platform powering today's mission-critical enterprise applications, including artificial intelligence, fraud detection and recommendations.
MySQL - The world's most popular open source database
ArangoDB - A distributed open-source database with a flexible data model for documents, graphs, and key-values.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
OrientDB - OrientDB - The World's First Distributed Multi-Model NoSQL Database with a Graph Database Engine.
SQLite - SQLite Home Page