Desktop Notifications - Light and fast applications for notifications mirroring between devices.
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.
AirDroid - Access Android phone/tablet from computer remotely and securely. Manage SMS, files, photos and videos, WhatsApp, Line, WeChat and more on computer.
UptimeRobot - Free Website Uptime Monitoring
Handshaker - Manage Your Android Phones at Ease
StatusCake - Website Uptime Monitoring & Alerts – Free Unlimited Downtime Monitoring