NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
Komodor - The Kubernetes native troubleshooting platform
SolarWinds System Management - Performance monitoring and management for applications, Websites, servers, storage arrays and virtual infrastructure.
ALog ConVerter - Server access log solution for finance and manufacturing
Nodeping - NodePing Server Monitoring and Web Site Monitoring. Simple but powerful Internet service monitoring.
Google StackDriver - Stackdriver provides monitoring services for cloud-powered applications.