Pusher Beams - Send push notifications programmatically at scale
Pushbullet - Pushbullet - Your devices working better together
Magnify - Push out beautiful website announcements in 10 seconds.
Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
Push Notification Preview - A simple tool for previewing push notification copy
Gotify - a simple self-hosted server for sending and receiving messages