Abusix - Abusix is a network security company that offers email threat protection and network abuse handling solutions to ISPs, Telcos, and Cloud/Hosting Providers to stop the rapidly growing problem of email-borne threats and other kinds of network abuse.
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.
Zabbix - Track, record, alert and visualize performance and availability of IT resources
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
NetVizura NetFlow Analyzer - NetFlow Analyzer is a solution for bandwidth monitoring and traffic analysis. It helps with traffic investigation, analysis and reporting
Better Uptime - We call you when your website goes down