NIXStats - SaaS monitoring tool for window/linux servers and websites. Think up-time robot but with more features.
Server Monitoring - A server monitor is a tool that monitors your server and website on close intervals and reports to you if it's inaccessible.
Zohno Z-Term - The Easy-to-Use Active Directory User Termination Tool
Nodeping - NodePing Server Monitoring and Web Site Monitoring. Simple but powerful Internet service monitoring.
Server Density - Trusted monitoring built by experts.
mackerel.io - mackerel.io is a server and application performance monitoring platform.