Qualys - Qualys helps your business automate the full spectrum of auditing, compliance and protection of your IT systems and web applications.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Amazon CloudWatch - Amazon CloudWatch is a monitoring service for AWS cloud resources and the applications you run on AWS.
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.
Google Cloud Platform Security Overview - Cloud Workload Protection Platforms
Prometheus - An open-source systems monitoring and alerting toolkit.