VoiceText for Slack - Voice notes w/ transcription in Slack
Skype for Slack - Move your slack discussions to a group skype call
Einote - Einote is a Chrome extension that allows Internet users to take notes on the fly with their voice right from any webpage.
Calls on Slack - Make voice calls in Slack
Phonic.ai - Phonic is the easiest way to collect audio or video in an online survey. Designed for market research teams, startups and academic researchers.
CallKite - Your website’s video call center in just one click.