Clyp - Clyp is the easiest way to record, upload and share audio. No account required.
Houseparty - Brining empathy to online communication.
Audio Hijack - Record any audio, with Audio Hijack!
Booyah - Video chat with up to 12 friends at the same time.
Loopback by RogueAmoeba - Get all the power of a high-end studio mixing board, right inside your Mac!
Airtime - Hang out with group video, share music & videos