OneSignal - Customer engagement platform used by over 1 million developers and marketers; the fastest and most reliable way to send mobile and web push notifications, in-app messages, emails, and SMS.
PushCrew - Push Notifications for Websites
Notix.co - NOTIX is an audience re-engagement service based on web and in-app push notifications that work for both desktop and mobile devices.
Pushover - Real-time notifications on your Android, iPhone, iPad, and Desktop
Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
iZooto - Engage your mobile and desktop web users with intelligent web push notifications.