Crisp Status Page - Monitor servers and let users know if something goes down.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Robusta - SRE Copilot for Kubernetes
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.
Komodor - The Kubernetes native troubleshooting platform
Prometheus - An open-source systems monitoring and alerting toolkit.