I spend far too much time watching people talk about games on youtube. I'll go first and fire off a few of my absolute favourites.
GMTK
Game Makers Toolkit is probably one of the most well known gaming youtubers. He's produced over 200 really well done mini-documentaries that focus on everything from Mario's Jump to how accessible games from 20XX were.
He's also in the process of making his own videogame, and is journaling that adventure through his own videos.
Jacob Geller
I believe Jacob is working over at MinMaxx right now, but he still finds time to put out some....very interesting content. Not all of it is videogame related, but the majority of it is, and most of that content is very unique and highly interested in talking about games in ways that I've never seen them spoken about before.
People Make Games
They're a relatively new kid on the block, but being a slightly larger team they're able to take on larger projects, such as how and why the videogame industry is failing the working class, how Valve's production line isn't as magic as you might believe or...why the Queen had a golden Wii.
New Frame Plus
Think GMTK but with a focus on the visuals of the medium. Some of my favourite content is his yearly round up of his favourite in-game animations, or the 2+ hour breakdown he did of the Sonic franchise's inability to keep to a standard. Heck, I got the family into that one.