Jepsen: databases, coordination services, and queues analyses

https://jepsen.io/analyses

Freezer

https://github.com/arqex/freezer
Immutable.js alternative

Datomic Database

http://www.datomic.com/
Built with Clojure
Immutable: you can get a view of the DB on any past moment.
Pluggable persistence: PostgreSQL, Cassandra, ...