I get a lot of laughs out of Vinesauce, if YouTube has my full attention (which unfortunately these days, it does not) it can really cheer me up if I'm feeling down.
I've developed a bit of a crush on JonTron recently, his humour and execution are perfect.
Ashens is hilarious. He can do a decent review of a genuinely good product, but his reviews of dollar store shit are fantastic, and his exotic/expired foods tasting segments are what got me clicking the sub button.
I'll listen to MrCreepyPasta about 90% of the time that I'm drawing. Just stick my headphones on, choose a creepypasta and get drawing. I find that when I'm drawing is the only time I can really sit down and LISTEN to a creepypasta. Reading them on page is a different matter though, but I think he's a great actor and with everything that goes into his narrations, he makes me feel the story a hell of a lot more than if I was reading it for myself. I guess that's the way to make a great dramatic reading.
If I'm not listening to his narrations while I draw, I'm listening to MichaelLeroi read a terrible creepypasta and rip on it with British humour. They never fail to make me laugh, and what I love about them just as much is how much they like to get involved with their fans, as they are still a relatively small channel. They livestream often, but I have a terrible way of missing the vast majority of these.
I'm probably missing a few, so this is not an exhaustive list at all. There are many others who I enjoy the content of but don't follow in the long term.