mostly music, and a lot of DIY.
i also use it as a source of information. to learn how to do things I couldn't before. I watch informative videos on things like herbalism, witchcraft, homesteading, etc.
recipes, nutritive info, conflicting dietary advice from doctors all over the world.
and every once in a while i'll watch Good Mythical Morning, The Try Guys, misc buzzfeed, etc. just for fun
John and Hank Green, segments from John Oliver's TV show, but I also get all of my music from Youtube. I don't know how any of those fancy newer platforms work so I avoid them altogether
I like catching up with some long time youtubers that I follow like CaptainSparklez (the only minecraft youtuber I watch, even though I don't play the game myself), TheKingNappy (great pokemon let's player, even though he has a "not-PG" rating, as he calls it, whatever that means), ShaddyPenguinn, CinemaSins, TVSins, FalseSwipe Gaming and music, too <3