Great Downloader easy to use can convert into multiple file formats. Fast and impressive
Video DownloadHelper - Browser extension to download videos from the Web
Virtual Audio Cable - Ever wanted to record your speaker output? (loopback) This is for you.
youtube-dl-gui - A cross platform front-end GUI of the popular youtube-dl written in wxPython.
Loopback by RogueAmoeba - Get all the power of a high-end studio mixing board, right inside your Mac!
Youtube Video and Audio Downloader - Download YouTube videos in all available formats and extract the original audio files.
JACK Audio Connection Kit - JACK Audio Connection Kit|Home