Search “DB Engines” for the current DB ranking. http://db-engines.com/en/ranking
Relational DBMS: Oracle, Mysql, Microsoft SQL Server, Microsoft Access, PostgreSQL, DB2, Sybase, SQLite
NoSQL – Document store: MongoDB, CouchDB,
NoSQL – Key-value store: Redis, Memcached,
NoSQL – Wide column store: Cassandra, HBase,
NoSQL – Graph DBMS: Neo4j