This is a chrome extension.

An actually random shuffle for large playlists, and without the lag. Based on https://github.com/raman-at-pieces/youtube-bookmarker-finished-code.

How to use:

1. Open playlist page and look for save button. If you can't see it try reloading the page.
2. Click save button. If your playlist has more than 100 videos, it will need to scroll down to load them all. Click the save button when everything is fully loaded. If it scrolls down again, repeat.
3. The playlist should now have been saved. To shuffle a playlist click on the extension in a youtube page.
4. Then click on the shuffle button next to the playlist you want to shuffle.
5. Then wait. The next video should play when the current one finishes but you might need to disable autoplay. Autoplay never works for me so I'm not quite sure about this.