I do subscribe to more than a dozen channels (just about, close to a dozen), only one of which is politics related
TheJuiceMedia (that's the "Honest Government Ads" people) because I like the people, I like their message, I"m a patreon supporter and sometimes I even share their videos here on this forum 😛
AKIHITO YO****OMI because watching that guy creating art in almost real time in front of my eyes is just fascinating
A number of hobby related channels (miniature wargaming and painting, with a focus on Horus Heresy and Kill Team)
Outer Circle, Rift Forge Studio, Black Briar Gaming, Cult of Paint, The Cult of Crafting, Grimdark Gamers
And some history related channels:
Drachinifel (my second favourite channel after Juicemedia), HistoryMarche, Kings and Generals, Invicta, History Matters (awesome series of 3 minute videos explaining things you didn't know you didn't know)
Besides that, using the search bar to check for things that just springs to mind....
Edit: Not going to list things like Microsoft Partner Source, MCP and similar as that will only be available to a minority of people with a very narrow focus for what they are looking for. Not a Youtube subscription as much as collections of Youtube links organized by topic on other sites