I subscribe to roughly 30 different channels, but I don't know if I'd describe them as cool. Most of them are nerdy repairs type contributors that also have a sense of humor about what they do. I also tend to lean towards contributors that haven't completely sold out to having their channel sponsored.
That being said, Pole Barn Garage (KC metro), Junkyard Digs (Ames area), and Watch Wes Work (NW Illinois) are probably my favorites because they're midwest based. I also really enjoy Sarah-n-tuned's stuff a lot because (see below...).
I like the channels that aren't some huge TV show production. The less "outside contributors" I see in the content, the better.
One trend I have noticed about a lot of the channels I subscribe to is Youtube is REALLY cracking the whip on them with regards to content. Several of my favorites - it's pretty apparent that they do nothing but channel related work 7 days a week, 365 days per year. One channel, Sarah-n-tuned - she literally never, ever takes a day off her auto projects yet also never takes on sponsorship. I watch her do all the work herself, every day, busting her ass to create content. There's an authenticity to her stuff that appeals to me big time. There is no huge production company backing her...everything you see, she does it all.
Imagine starring in a half hour hit TV show that cranks out a new show every week where you're the star, producer, director, writer, cinematographer, editor, agent, advertiser, manager...you do literally EVERYTHING YOURSELF. There are no days off. You have zero personal life. That's all you do because if your goal above all is to be successful yet maintain control of every aspect of your channel, you really do have to do everything yourself.