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.
RetroArch - RetroArch is a frontend for emulators, game engines and media players.
UptimeRobot - Free Website Uptime Monitoring
LaunchBox - LaunchBox is a portable, box-art-based games database and launcher for DOSBox, emulators, arcade cabinets, and PC Games. Download it free!
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Batocera.linux - Batocera.linux is an open-source and completely free retro-gaming distribution that can be copied to a USB stick or an SD card with the aim of turning any computer/nano computer into a gaming console during a game or permanently.