Daily.co for Intercom - Free video calls & screen shares embedded in Intercom
Landing Pages in MailChimp - Easy to build, custom landing pages for free
Pluot Communications - Big-screen video conferencing for startups
Viral Loops for Startups - Virality for startups made easy 💪
WhatsApp - WhatsApp Messenger: More than 1 billion people in over 180 countries use WhatsApp to stay in touch with friends and family, anytime and anywhere.
Carrd - Simple, responsive one-page site creator.