One of my favorite channels is musicalbasics. Lionel (I’ve talked about him before) makes music. He also sells some of his songs as sheet music. I also like Numberphile and Computerphile. Vi Hart  is also worth a look if you like math. I love Sick Science (one of Steve Spangler’s youtube channels). ElectryDragonite makes cool LEGO creations (like candy machines that take money). Those are my favorite channels.