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
Syslog-ng - Syslog-ng decreases the quantity and improves the quality of data, thus enhancing the capacities of your SIEM solution.
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.
Fortinet FortiAnalyzer - Fortinet FortiAnalyzer is a powerful product for Security Fabric Analytics and Automation.
Prometheus - An open-source systems monitoring and alerting toolkit.