Suprvise is a real-time health monitoring and errors tracking dashboard.
Is It Down Right Now? - Network & Admin
WebGazer - Monitor your website's availability with WebGazer, review its performance and get instant notifications when your website goes down. No installation required and free plan available.
Site Down - Site down outage and downtime reports from SiteDown.co
Monitority - Simple website monitoring service (sms/email alerts)
Is it Down? - Is it down can check if a website is down or is it just your PC that can not access it.
Hyperping - Cheap uptime and performance monitoring with detailed reporting and flexible alerting