The most recent one which I'm currently working on is to take notes on the structure of SaaS product intro videos (the one you find on the landing page, usually above the fold)

Another one I had in the past that it will make easier is to add time marks on the video description (youtube segments the timeline and adds a section list to jump between the marks)

I think it can also be useful for people taking online classes or learning from videos

Another one I forgot, transcribing video tutorials into a written guide.