Zabbix - Track, record, alert and visualize performance and availability of IT resources
SIREN.io - Siren is an investigative intelligence platform.
Datadog - See metrics from all of your apps, tools & services in one place with Datadog's cloud monitoring as a service solution. Try it for free.
DataWalk - DataWalk is a software platform to connect numerous large data sets, both external and internal, into a single repository for fast visual analysis.
Prometheus - An open-source systems monitoring and alerting toolkit.
SpiderFoot - Open source intelligence (OSINT) automation tool.