Beats - Beats is the platform for single-purpose data shippers that is installed as lightweight agents and send data to machines to Logstash or Elasticsearch.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
packetbeat - Packetbeat is an Open Source Application Monitoring and Packet Tracing (Packet Sniffer) system.
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.
SolarWinds NPM - Advanced network monitoring for on-premises, hybrid, and cloud. Download a FREE 30-day trial of SolarWinds Network Performance Monitor (NPM) today!
Prometheus - An open-source systems monitoring and alerting toolkit.