Wazuh - Open Source Host and Endpoint Security
Zabbix - Track, record, alert and visualize performance and availability of IT resources
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.
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.
Fluentd - Fluentd is a cross platform open source data collection solution originally developed at Treasure Data.
NewRelic - New Relic is a Software Analytics company that makes sense of billions of metrics across millions of apps. We help the people who build modern software understand the stories their data is trying to tell them.