Notif.me SDK - A Node.js lib to send all your transactional notifications
BlockchainI.CO - Research, ratings and analysis on upcoming ICO’s
Ethereum Push Notification Service - Protocol for incentivized, blockchain based notifications.
Coin Demo - Visual demonstration of how bitcoin transactions work
Blockbutler - Real-time transaction notifications for the blockchain
Blockchain Startups Map - Map & searchable database of 430 companies in 64 categories.