Downie - Video download for OS X. Downie supports at this moment over 1,000 different sites.
CONV. - Convert YouTube video to MP3, GIF or MP4
Save IGTV - IGTV Downloader - Save IGTV Videos on any device with the fastest IGtv video downloader.
Viddit.Red - Download Reddit Video - helps download video from reddit, with audio. works with many different reddit posts and embeds.
Yout - YouTube to Mp3 Converter
Thonny - Python IDE for beginners