YouTube is a great place to find great content, unfortunately you have to dig to find it. "Surface" YouTube is a terrible cocktail of reaction videos, clickbait, and low effort content.
Luckily I've been able to find a decent number of great channels, so here is my list:
Probably one of the best YouTube creators around, he makes videos over a broad range of topics.
Does a great video game like representation of historic battles with tons of background and history mixed in.
Bill Hamock does a great job explaining engineering and technology principals and designs.
Pop culture "love letters"
Much like CGP Grey (they do twin videos sometimes), covers a lot of different topics
Discussions about cinema
Covers topics from dance to military history, but mainly focuses on history
Great creator who covers many topics of warfare
Videos about language, how they work, and their history
Another channel about cinema
A man who never speaks builds the most incredible things out of mud and muscle
Covers a ton of topics about various engineering topics and issues
This is more of a series than a collection of videos, it covers World War I, week by week
Some of their more recent stuff is meh, but their Philosophy, History, and Politics videos are great
Great videos about things you might not know
Videos about engineering topics that changed the world