One, Veritasium. Content like this didn't (perhaps even couldn't) exist before YouTube. The science TV shows and even many books don't go into as much user-friendly depth as this does. You'd have to go to college and pay to get content even remotely close (and still, based on prior experience, not as good).
Two, any one of many How To DIY channels. They show you how to do things you're unlikely to find elsewhere. Where else will you find someone willing to tell you how to change your oil and filter on a [random year & model] car for free? How to wire up a light switch to code? How to clean your sink drain? Certainly not the paid professionals.