VB-Audio Virtual Cable - Connect Audio Applications together with a Virtual Audio Device
VAcard - [NOTE: You can download the application from ...
SoundDesk Virtual Devices by LoudLab - SoundDesk Virtual Devices - Software devices to route audio across macOS.
vsound - Vsound a virtual audio loopback cable - Vsound is an application which allows you to digitally record the output of another program such as RealPlayer.
Virtual Audio Cable - Ever wanted to record your speaker output? (loopback) This is for you.
iShowU Audio Capture - iShowU Audio Capture is an extension to OS X to record audio from your computer.