https://eqlz.github.io/distraction-free-youtube/
I want to watch a teaching video on programming without suggested videos on the right or comments below. Just show that one video on the page.
Especially suggested videos, I can't remember how many times I clicked a seemingly entertaining video, and being sidetracked from my original learning.
You can play a music video on loop.
Youtube IFrame Player API offers a loop parameter.
This does the trick:
<iframe src="https://www.youtube.com/embed/VIDEO_ID?playlist=VIDEO_ID&loop=1">