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.
Mailshake - Mailshake lets you build your professional network through a smart and intuitive approach to cold emailing.
ZoPush - Personalized Browser Push Notifications for Web and Mobile.
Batch - Batch is an intelligent push notifications platform for mobile apps.
PushBots - Light SDK for mobile push notifications
PushCrew - Push Notifications for Websites