Redis - Redis is an open source in-memory data structure project implementing a distributed, in-memory key-value database with optional durability.
Microsoft SQL - Microsoft SQL is a best in class relational database management software that facilitates the database server to provide you a primary function to store and retrieve data.
SQLite - SQLite Home Page
MySQL - The world's most popular open source database
PouchDB - Open-source JavaScript database inspired by Apache CouchDB that's designed to run well within the browser
PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.