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