TigerGraph DB - Application and Data, Data Stores, and Graph Database as a Service
MySQL - The world's most popular open source database
Azure Cosmos DB - NoSQL JSON database for rapid, iterative app development.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
ArangoDB - A distributed open-source database with a flexible data model for documents, graphs, and key-values.
SQLite - SQLite Home Page