RPi-Monitor - RPi-Monitor is a tool that provides all the connected system peripherals properties and current metrics.
Pingdom - With website monitoring from Pingdom you will be the first to know when your website is down. No installation required. 30-day free trial.
Venmon - Compact size system resources monitoring utility and multi-ping tool for Windows
Scout - Application Monitoring that finds what you can't see in charts.
Checkmk - Checkmk - the software for effective IT monitoring
Trimgle - Web page and json monitor, get control of information