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.
Wallcat - Enjoy a new, beautiful wallpaper, every day.
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring
Splashify - Beautiful desktop wallpapers for Mac and Windows
Better Uptime - We call you when your website goes down
Irvue - (previously Unsplash Wallpaper) Gorgeous wallpapers on your Mac.