There are so many channels on Youtube dealing with chess, and I believe most chess players are better informed than I am about which channels are the best. I would like to just recommend my favourites:

Silicon Road, with Matthew Sadler, is the only chess channel I have ever watched with some consistency.

Killer Chess Training, run by Jacob Aagaard and Kallia Kleisarchaki, is a very serious channel, although it is mostly a channel for advertizing the courses that you can sign up for. I am a bit partial here, since I have worked for them.

Here is a video from one of my courses (the first of 6, or 8, I believe).

Go:

Go Game Series is simply the best channel that Youtube has ever seen, for more ambitious players. Jianqiu Chen, who runs the channel, is an excellent teacher, and he goes far deeper than any of the other channels.

Go Magic is mostly aimed at kyu players, but they also have some podcasts and other material.

Michael Redmond is the only Westerner to ever have reach 9P, and his channel is obviously top notch.

Dwyrin is a good channel for beginners and lower kyu-players.