Amazon Aurora - MySQL and PostgreSQL-compatible relational database built for the cloud. Performance and availability of commercial-grade databases at 1/10th the cost.
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
MongoDB - MongoDB (from "humongous") is a scalable, high-performance NoSQL database.
MySQL Community Edition - MySQL :: MySQL Community Edition
Microsoft SQL Server - Microsoft Azure is an open, flexible, enterprise-grade cloud computing platform. Move faster, do more, and save money with IaaS + PaaS. Try for FREE.
SQLite - SQLite Home Page