I wish people would stop linking MrS0m30n3's GUI. It's no longer maintained and other fork(s) are active. The one which so far retains the look is called yt-dlg now.

We have a big list of youtube-dl GUI's over on /r/youtubedl's wiki: https://www.reddit.com/r/youtubedl/wiki/info-guis

Do any of those use this Gooey framework?

Great, thanks!