The Youtube channels I would recommend are the following:
Tech/Science
S3 - The stories of people working to change the world.
Modern Day Eratosthenes - A great STEM communicator who provides a moderate level breakdown of STEM topics. Videos are less than 12 minutes long.
Ziroth - This channel focuses on highlighting new science and engineering projects that are helping the world transition to a zero carbon future!
Speculative Science
Isaac Arthur - This channel focuses on exploring concepts in science with an emphasis on futurism and space exploration, along with a healthy dose of science fiction. While we explore many concepts and technologies that are far beyond us now, we try to keep everything inside the bounds of known science or major theories.
Analytical Tech News/Stories
TechAltar - Analytical videos about tech companies [and their products or services].
Tech Business/Economics/History Video Essays
Asianometry - One of my favorite YT channels. He does a great job producing high quality videos about tech history, tech related economics, and sometimes dives into what that latest tech is and how it might play a part in our future.
Humorous Business Journalism
Good Work - "Edge-cutting" business journalism, with a healthy dose of humor mixed in. Actually covers things that you might want to know more about in the realm of business, trading, and why the American economy is so freaking weird.
The Making of a Movie/TV Show
It Was A Sh*t Show - Making stuff is hard, especially in the entertainment world when there are millions of dollars on the line. And we are going to talk about these disastrous, never ending, and sometimes dangerous productions. With video documentaries and a companion conversational podcast, It Was A Sh*t Show is an entertaining look at some of your favorite films and tv shows, and why they were such a nightmare to make.
Frame Voyager - Mini-documentaries on films without the clickbait negativity.
Mini/Full Documentary Makers
Peter Dibble - Obscure history from the Pacific Northwest and beyond. I recommend checking out America's First Cross-Country Auto Race.
Kirby Ferguson - He's best known for his documentary series called, Everything is a Remix. He made an updated and extended version of it. I recommend it.
If you want to watch an Irish dude play and talk about a variety of obscure PS1 games, everyone should definitely check out Sean Seanson (currently at 44k subs). He has 2 ongoing series where a game is picked at random and he checks it out, one for western releases and another for japan exclusive PS1 games.
Majuular (166k subs) also does videos on mostly obscure or forgotten games. I really enjoyed watching his "I played every RPG on the " videos, the one for the Saturn showed up some real gems.
Moon Channel (182k subs) is one of the "slow content creators", which makes nearly every video he posts a great watch. He has great stuff like "Why do Japanese games love Brazil?" and "Gacha Games and the Korean Gender Wars" - the latter an incredible look into how and why Korean culture is the way it is today.
NeverKnowsBest (329k subs) is yet another gaming channel, focusing on very long videos. One that I do recommend to any Bethesda fan is "Lies, Hate and the story of Emil Pagliarulo" (it's an eye opener and I am guilty of having joined the "it's all Emil's fault" bandwagon due in no small part to the videos he references). If you want to keep it to genres, his 2 most recent videos are "The Entire History of Japanese RPGs" and "An in-depth look at Romance in video games" - the latter shows up a number of famous dating sim games.
Basement Brothers (33k subs) is a channel devoted almost entirely to 80s and 90s Japanese computer games. So, if you were ever curious about PC-88 and PC-98 games, or the origins of franchises like Ys or Legend of Heroes, this is the place to find that.
As a bonus, SAMA Study of Antiquity and Middle Ages for history stuff. It's very well researched stuff, often citing studies that follow DNA heritage among human groups to get an idea of when they migrated from one place to another.