CodeGuard - CodeGuard provides website backup, monitoring, and malware remediation services to small and medium businesses.
NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
Amazon AWS - Amazon Web Services offers reliable, scalable, and inexpensive cloud computing services. Free to join, pay only for what you use.
OpsDash - All-in-one solution for monitoring servers, services, uptime and databases. Curated Dashboards. Rule-based alerting.
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.
Monitornator - Server monitoring made simple