Selldom - Make money from your unused domains 💸
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.
Tool.Domains - Search free to register expired domains
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
DomainWatch - Domain Monitoring Made Easy
Better Uptime - We call you when your website goes down