InfluxData - Scalable datastore for metrics, events, and real-time analytics.
OpenTSDB - OpenTSDB is a distributed, scalable Time Series Database (TSDB) written on top of HBase.
Cortex Project - Horizontally scalable, highly available, multi-tenant, long term Prometheus.
Reconnoiter - Reconnoiter is a monitoring and trend analysis system designed to cope with large architectures...
TimescaleDB - TimescaleDB is a time-series SQL database providing fast analytics, scalability, with automated data management on a proven storage engine.
Thomson Reuters Datastream - Thomson Reuters Datastream is a financial time series database that allows to identify and examine trends, generate and test ideas and develop view points on the market.