Ethereum Push Notification Service - Protocol for incentivized, blockchain based notifications.
TechEvents.co - Tech and startup events aggregator
Blockbutler - Real-time transaction notifications for the blockchain
Event Hunt - Startups and Tech Events Curated By Locals
Notif.me SDK - A Node.js lib to send all your transactional notifications
Calendify - Calendify is an event community where you can share, publish, and subscribe to event calendars. It helps you to stay informed about what you are interested in and what is yet to come.