MySQL - The world's most popular open source database
OrientDB - OrientDB - The World's First Distributed Multi-Model NoSQL Database with a Graph Database Engine.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
SQLite - SQLite Home Page
ArangoDB - A distributed open-source database with a flexible data model for documents, graphs, and key-values.
Oracle Database 12c - Simplify database management and automate the information lifecycle with maximum security.