Redis: In-Memory Key-Value NoSQL Database:
https://redis.io
Cassandra: One of the most powerful production NoSQL systems:
http://cassandra.apache.org
MongoDB: Document-based NoSQL database:
https://www.mongodb.com
Vertica: Community Edition:
https://www.vertica.com/try/
Teradata: Aster Community Edition:
https://aster-community.teradata.com/community/download