PostgreSQL - PostgreSQL is a powerful, open source object-relational database system.
Oracle Berkeley DB - Oracle Berkeley DB is an extensive embedded key-value database library that is providing support with scalability in performance for data management services and applications.
MySQL - The world's most popular open source database
solidDB - Relational Databases
MariaDB - An enhanced, drop-in replacement for MySQL
EXtremeDB - EXtremeDB is an extensive database management software that is creating an impact via extracting the actionable data for the predictive insight that, in turn, values the entire infrastructure.