SQL Server (*) Microsoft (NASDAQ: MSFT) makes SQLServer for enterprise and cloud computing and the Access Database for personal computers.
MariaDB (mariadb.org) MariaDB is a fork of MySQL created by Michael Widenius, founder of MySQL, after Oracle purchased Sun Microsystems, which owned MySQL.
MySQL (www.mysql.com) MySQL began as an open source database created by Michael Widenius in 1985. It named for his daughter My. Widenius sold his company to Sun Microsystems in 2008. Sun was acquired by ORACLE in 2010.
PostgreSQL (www.postgresql.org) PostgreSQL is an advanced open source database developed by The Postgres Group.
SQLite (sqlite.org) SQLite is an embedded open source, public domain database.