Houseparty - Brining empathy to online communication.
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.
Booyah - Video chat with up to 12 friends at the same time.
Quickie - 3-60 second video calls with your friends
Slack - A messaging app for teams who see through the Earth!
Messenger Video Calls - Facebook Messenger, now with HD video calls