The best maker YouTube channels

Over at Cool Tools, Kevin Kelly reviews over 40 YouTube video channels by makers, experimenters, and explainers. It's a great list. I'm subscribing to all the ones I haven't already subscribed to.

I have descending into the YouTube click hole. Forget TV, movies, Netflix; I spend most of my discretionary media time watching YouTube tutorials. I go to them whenever I need to learn anything, and in particular when I need to make or repair anything. Nothing appears missing in the YouTubeverse. The most obscure esoteric subject, item, skill, technique, problem will have five videos dedicated to it. At least one will be good. Against this very uneven quality of the average random YouTube episode, I have discover a good shelfful of dependable high-quality YouTube channels dispensing amazing information on a regular basis. Below are the YouTube channels I currently subscribe and return to often. They are informational, rather than entertaining, and they are biased to makers and do-ers. I have divided them into four groups: Experimenters, Makers, Explainers, and Nichers -- esoteric interests that probably wont appeal to many. Dont take the categories too seriously; there is much overlap. I emphasize that these are the channels I personally subscribe to, and so reflect my interests, and do not include such obvious other maker-type channels like food, cooking, travel, makeup simply because those are not my interests. But I for sure have missed some great channels. So in the comments please tell me what channels you subscribe to. To be most useful, state what they are about, and why you think they should be included.