OpenMediaVault - OpenMediaVault is the next generation network attached storage (NAS) solution based on Debian Linux.
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.
TrueNAS Core - TrueNAS Core (formerly FreeNAS) is a storage operating system strong and robust enough to meet the needs of enterprise level businesses.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
XigmaNAS - File Sharing, OS & Utilities, and Security & Privacy
Better Uptime - We call you when your website goes down