I spend most of my time watching YouTube in the Food and Drink part, so...
Binging With Babish: The best torso on the Internet, recreates food from TV and movies, makes everything look delicious unless it's not supposed to be, as chill as they come.
Cocktail Chemistry: Another amazing torso, only this one makes drinks and listens to a lot of jazz. Possibly even more chill than Babish.
Strictly Dumpling/Mark Wiens/The Food Ranger: I always put these three together because they're the holy trinity of Youtubers who travel around the world eating awesome food. They usually make long vids too, so they're perfect for having on in the background.
Food Wishes: His ultra sing-song voice and mannerisms may slightly grate for some ("HellOOO this is Chef John from FOOOD wishes dot com withhhh...Lobster Mac and Cheeeese! That's right!"), but he is the OG Dude of Food on YouTube. Addicted to Cayenne.
Hiroyuki Terada: Makes the most awesome sushi on YouTube and says "good afternoon". Videos also feature a mysterious cameraman-cum-interviewer who Chef Hiro either barely tolerates or dearly loves. Not afraid to kill in the quest for a damn good video.