Mr Grow It is the first that comes to mind. This is probably the most decently informed channel while also keeping content simple, and videos short but concise.
Home Grow TV is a fantastic, well-polished channel that's very fun to watch. He's in Colombia, so it's interesting to see how another part of the World accesses their genetics, equipment etc. (I mean, he's sponsored now so it's probably easy, but whatever. Still a fun watch)
I still love watching Mr Canucks Grow, I don't care about all the hate he gets thrown. Also a well polished channel, but basically don't do most of what he does, lol!
I used to like Mr GoodBuds but HOLY FUCKING SHIT his camera work gives me seizures. get a tripod, dawg, damn.
I used to like Bill Ward's channel, but most of what he grows now is larfy crispy autos. He uses cool equipment though, the big turntable and his scrog webb. Still worth a skim.
Vader OG and Chad Westport also post awesome content, not necessarily "for beginners" but still good content to watch to brush yourself up on info you'll run into down the line, so to speak.