Ethereum Live - All the latest updates on Ethereum
Blockbutler - Real-time transaction notifications for the blockchain
Ethereum Price - ETH live price + updates from the industry
Notif.me SDK - A Node.js lib to send all your transactional notifications
Ethereum Syllabus - A complete Ethereum learning track, packed with resources
Pusher - Pusher is a hosted API for quickly, easily and securely adding scalable realtime functionality via WebSockets to web and mobile apps.