Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
PushEngage - Personalized Browser Push Notifications.
Pushbullet - Pushbullet - Your devices working better together
Gotify - a simple self-hosted server for sending and receiving messages
PushCrew - Push Notifications for Websites