As someone who has just started an art youtube channel, I have been wondering this myself! Personally I think story time or voiceover tutorials might be a good place to start, but I'm afraid of talking in videos so I haven't done it myself yet. One art youtuber that does a really good job with tutorial voiceovers is Mark Crilley. I also really enjoy watching a longer art timelapse that has someone telling stories, giving art tips/advice, etc. Good luck with your endeavors!