The Prometheus monitoring system and time series database.
TiDB is an open source distributed HTAP database compatible with the MySQL protocol
Scalable datastore for metrics, events, and real-time analytics
CockroachDB - the open source, cloud-native distributed SQL database.
An open-source graph database
Fast, Distributed Graph DB
An embedded key/value database for Go.
Vitess is a database clustering system for horizontal scaling of MySQL.
GitHub's Online Schema Migrations for MySQL