Coinbase - Bitcoin, safe and easy.
Opta - Opta is a new kind of Infrastructure-As-Code framework designed for fast moving startups.
CoinSparrow - A marketplace for buying services with crypto
Chain - The Block Chain API for Developers
CryptoMarket - Price tracking app for bitcoin and altcoins
Cal.com - Cal.com (formerly Calendso) is the open source Calendly alternative.