Google Open Source - All of Googles open source projects under a single umbrella
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.
Open Source @IFTTT - A collection of IFTTT OSS projects.
Truepush - Unleash limitless possibilities with Truepush and save up to $600 monthly. Free up to 10K Subscribers on all features.
Code NASA - 253 NASA open source software projects
PushCrew - Push Notifications for Websites