While not exactly what you are asking, check out Nebula as it has a lot of long form content that is not slop because they actively monitor it.

Not sure if these are what you're looking for, but:

• Dr. Becky [professional commentary on astronomy and astrophysics]

• Anton Petrov [professional commentary on astronomy and astrophysics]

• What's Going On With Shipping? [videos about the ins and outs of international maritime shipping]

• Not Just Bikes [focuses on the many ways urban infrastructure can be improved]

• Sampson Boat Co. [~seven years worth of videos where Leo rebuilds a 1910 gaff cutter from the keel up. Currently sailing it back to London to participate in race the same boat won a century ago]

• Primitive Technology [builds cool things with sticks, mud, water and pond scum]

• Bad Obsession Motorsport [bought an old mini-cooper and shoved an engine from a Celica GT-Four into it]

• Practical Engineering [a practical look at engineering projects that most people ignore, mostly because they're underground]

• B1M [videos focusing on large mega projects like tunnels and nuclear reactors]

• Jay and Mark [map guys that rightfully complain about Londons infrastructure]

• Florian Gadsby [skilled (practised) potter that makes really satisfying pieces]

There are also channels that are focused on the war in Ukraine and related international shenanigans (in order of avg. video length):

• Perun

• Denys Davydov

• Reporting from Ukraine

• Suchomimus (poor chap made a channel to nerd out about dinosaurs, then the Russians attacked...)

Also check out ytch.xyz; It serves videos from a curated list of channels such that it behaves like cable television.

Also also check out nebula.tv if you can afford it.

Usually not as long, but the PBS stuff and Dr Becky are pretty good for astrophysics.

I like:

Technology Connections. Alec is a refrigeration cycle enthusiast from the American Midwest in a tweed jacket who talks about gadgetry. He'll change your understanding of dishwashers.

History For Granite. Join him to explore ancient Egypt. A no bullshit no ancient aliens channel focusing on old kingdom Egyptian monuments, particularly the pyramids of Giza and Dahshur. His hot takes include "The ascending passage of the Great Pyramid is built of lower quality limestone, possibly because the higher quality Tura limestone used for most passageways wasn't available. As the passage ascends, you can see the work getting more consistent and gaining quality, as if the masons were gaining skill working with this inferior material." And he casts solar eclipse quantities of shade at Zahi Hawass. It's hilarious.

Cathode Ray Dude. A computer and video hardware enthusiast from the Pacific Northwest. He'll find some electronics artifact and explore its quirks and features, including a whole series on weird old laptops.

Paul Fellows. Bri'ish astronomer type who delivers short-ish briefings on astronomical objects. "Once Around: The Large Magellanic Cloud." I'm getting to where I prefer his content to SEA or Astrum.

TierZoo. Animal documentaries in the style of video game commentary. Animals are player characters in a massively multiplayer game called Outside. A typical video will be titled "Are snakes OP?" and he will rank various snakes on a tier list. "Next we have the rattlesnake. Rattlesnakes have spent evolution points on the rattle ability, a mid-level intimidation and area denial attack intended to evade encounters with carnivore mains." The fact he's been able to keep up this shtick so long is the most entertaining part.

Veritasium

Fren

Johnny Harris

Compterphile

3blue1brown

tldrNews (several channel each for different region)

RealLifeLore

Money and Macro (actual economist, not finance bro)

A few channels I like that I think should fit. AFAIK none of them use AI whatsoever.

Stefan Milo (Prehistory/Archaeology)

Told in Stone (Ancient History)

World of Antiquity (Ancient History)

The Pharao Nerd (History)

Trey the Explainer (History and random topics)

Anton Petrov (Space and Science)

Big Joel (Culture/Media)

STRANGE ÆONS (Internet culture and random stuff)

If you are interested in (astro)physics, here are two channels which i enjoy and can assure for their correctness on research topics:

Dr. Becky Astrophysicist talking about what's happening in space from planets currently visible by nakedness eye to new impactfull research papers. She explains everything in an approachable way.

Angela Collier Theoretical physicist, makes long story telling videos about physics and societal topics surrounding research. Most videos are >50 minutes, some are more than three hours. However, they often stray from the original topic.

For some talk about philosophy, I can recommend Philosophy Tube. Most videos are somewhat short of an hour, but explain some philosophical topic in an approachable and interesting manner. Just don't be detered by her extraordinary costumes for each session. I think she research the philosophical questions quite well.

No one seems to have mentioned Steve Mould.
Super specific topics, interesting (to me anyway) and definitely no slop.
Edit:mentionded?

Don't see "Half As Interesting" listed here. His stuff doesn't usually go super deep, but I've learned a lot from him.

And just recently he was accused of using AI for a thumbnail and this was his response:

CRD and tech connections is all I watch really.

SmarterEveryDay is cool, it's a former NASA engineer just explaining cool shit. I'm a fan of his 'how do helicopters work' deep dive, and the world's greatest archer videos.

Veritassium is kinda the same thing, though I don't know his stuff quite as well.

More perfect union, according to Nicole, Zac rios

3 of my favorites in last few months.

Darknet diaries is the shit for podcasts. Also on YouTube.

PBS and Nova are good. Science Channel as well. Most vids are short but they put out some banger full length documentaries every so often.

History Time is also really good. The length of the vids can be hella long.

The History Channel has some cool stuff too.

Look at the list of creators on nebula and check their videos out, I think most of them should fit the bill.

If you find something you like, you can get a nebula sub (or lifetime pass) and cut out all the YouTube nonsense from the experience too!

allegedly Scary Interesting uses no AI generated content

Scary Interesting does some horror documentary stuff about, idk, scary situations people have been stuck in. No AI images, which is saying something, cause he always has some kind of background or graphic going.

LaurieWired

I like Matt Orchard Crime and Society (MOCaS). Like the name suggests, he does long format videos usually on crimes that are either bizarre or unusual for one reason or another. What makes the videos interesting is his sort of cynical take on it and the easy-to-follow dissection of whatever he's talking about. The focus is not on the gore or shock value, rather the morals involved, human behavior and often the law.

Not quite documentaries, but Clabretro makes long videos where you sort of learn about old computer equipment along with him as he figures out how to use a new thing he got. He used to use LLMs to try to figure stuff out in his videos which was a little annoying but he doesn't seem to anymore.

plus he has a cute cat named chloe

I have some regulars, probably more mid length than long form but they all have the occasional longer piece every so often:

History with Kayleigh - Charming Dutch creator with a focus on pre-historical human and hominids

Extra History - Cartoonified History with a humorous style

Flight Formula - Aviation History

History Buffs - Historical Analysis of Movies and TV

Technology Connections - Ascerbic presentation of technology often delving into the historic context

Gavin the Medievalist - Dr of English who specialises in medieval literature

Four Keys Book Arts - Calm and Patient Book Binder, sidelines in paper marbling

Noah Caldwell-Gervais - Video game analysis, super in depth with a focus on games as narrative

Missing a heap but those are the channels that sprang to mind.

This is the best, most comprehensive list I've found: https://www.clicknourishment.com/

LEMMiNO's production quality on his mystery documentaries is brilliant.

Ahoy mainly focuses on aspects of video game history and video game weapon design. I love his voice.

3Blue1Brown for pure mathematics.

There's slop, slop, slop, information and slop. It hasn't got much slop in it...

Cathode Ray Dude he does 1 hour plus videos on the history of a niche product or technology. He just did one that is 2+ hours on how they film tvs for movies. https://www.youtube.com/watch?v=qicQUvSUbPM

Just watch stuff from before 2023 or so? There's still lots.

IF you like warhammer 40k or want to get into the lore (it's god damn insanely deep and interesting) there are a few VERY good videos that are multiple hours long that pretty much come out on a weekly basis. https://www.youtube.com/@Luetin09 is my favourite. if I have nothing to do one a weekend afternoon i'll just put his vids on while I do some dev work or play around with my pc configs. each video is easily 2+ hours. and it's just lore.

I don't even know how to play WH40k, I don't own any of the minitures, but damn do I know all the lore because of his vids.

pbs eons, there are bunch of channels related to this one, some people on reporting on paleontology/new discoveries, or bio, i like how some people in the comments try to accuse the channels of AI without actual evidence. almost all the influencers AI for thier thumbnails, which i find cringey.

i would be careful watch pbs terra though, because there seems to be some sort of misinformation(like the alleged experts are speaking from an misinformed point of view), like how they are trying to save american chestnut species being devestated by blight, but doesnt go into detail(omit) why they are using the chinese hybrid to prevent disease, which makes it not a natural species since it was the chinese one that spread the disease in the first place, same goes with the devil holes pupfish(claims they are saving the species but doesnt really say why its being hybridizing with another species). there is just something off about that channel that doesnt have with the other pbs channels.

I've enjoyed DW Documentaries since I found them on a now defunct community TV channel back in the early 2000s. The format is the same now as it was then, so if they've worked in some AI slop, I haven't noticed. Topics are varied - science, history, politics, the environment, how local traditions of varying places cope with change - as are the run times.

Some examples:

Zanzibar - Island Paradise in Flux

Father Unknown? Life as a Sperm Donor's Child

Organic Farming as a Career Choice - Italy's Young Farmers

Neutrios: Do They Reveal the Secrets of the Universe?

The Swiss Bar Fire Disaster - Life After the Nightmare

Toxic Colonialism: Secret Chemical Warfare in Algeria

Strong Women: The Fight for Self-Determination

Muscles - More Than Power and Pumping Iron

Final Days Full of Life - Hospice Stories

Opioid Crisis in the US Part 01: Business and Addiction

Opioid Crisis in the US Part 02: Business and Addiction

Tech Ingredients - DIY-ing machines that seem way more complicated than they actually are

AvE - tool teardowns with the kind of crude humour you only get from being a spannerjockey

Greenhill Forge - Chap that builds homesteading/self sufficiency/off-grid equipment, brilliant at explaining the underlying principles without any jargon

Maximus Ironthumper - An off-grid living guy that's currently building a portable pipe organ in an old Zil truck (and refurbishing said truck in the process)

Styropyro - Master of the question "How dangerous can I make this high voltage device/ Laser without dying?"

Nilered /Nileblue - A mad scientist with the budget to do things like 'making a bacon flavoured apple' just for the hell of it

Dankpods - A channel with the widest variety of music tech and creator of the "Nugget dip" - a series about looking at second hand MP3/phone/early 00's tech that ended up in second hand stores

Alexander the ok - Highly researched and well written videos on topics such as "What is the dumbest nuclear bomb ever put into service?"

Just to name a few off the dome in a variety of Science/STEM topics

I'm a big fan of the b1m.

https://youtu.be/EruSZNI4th4 <- tunnel under the Faroe islands & world's only undersea roundabout

For specifically media discussion and history discussion, OverlySarcasticProductions

Joe Scott is good for this.

Time Ghost's channels are, IMO, the gold standard for history content. Its very in-depth, but they've so-far covered WW1 on their The Great War channel, WW2 on their World War 2 channel, interwar periods, and their current focus is on the Korean War on their channel, The Forgotten War by Indy Neidell.

All of their channels focus on covering these time periods chronologically - usually one episode a week, covering that week's events. Most of these individual episodes are 10-20 minutes long, but again, they release a new one weekly, so it will take a long time to catch up. As well as these weekly episodes, they also create some specials covering specific topics, and they produce the occational long-form documentary, such as their 12 hour long video on Pearl Harbor or their 24 hour long video on D-Day.

If you like car stuff, I got lots. Some plane stuff, too.

Eleanor Janega does great things on history, particularly the middle ages and adjacent.

History Hit does good stuff.

PBS Spacetime for serious physics and cosmology, much of which goes over my head.

Veritasium is my favourite, especially for math stuff. The videos tend to be about 20m.

Check out Simon Whistler and his team’s channels. Tons of informative stuff and I think they make a sizable portion of all YouTube content lol

https://www.simonwhistler.com/

Lots of good channels mentioned that I won't repeat, but didn't see Modern History TV yet.

If you like long, human-made, interesting but also a bit leftfield documentaries, you could do a lot worse than Jon Bois.

Example - a four part series about the history of the telegraph, told through an extended metaphor involving the two main characters in 90s sitcom, Home Improvement.

Highly recommended, as is his other stuff. He has a couple of deep dives into the weird histories of the Atlanta Falcons and the Minnesota Vikings that are also well worth watching

For video games:

https://youtube.com/@neverknowsbest

Several hours-long dives into either a specific game, a series of games, or even the entire history of video games. His voice somehow locks you in. You won't even feel the time go by and you will feel richer for the experience.

For interviews, Lex Fridman.

Historia Civilis https://youtube.com/@historiacivilis

Cambrian chronicles https://youtube.com/@cambrianchronicles

Type 56 https://youtube.com/@type56_ordnance_dept

Highly suggest Swegle Studios if you’re into weather and other natural phenomena. Full disclaimer though, he tried AI visuals once or twice in the past but got absolutely reamed for it and doesn’t do it anymore

PBS SpaceTime, my personal favorite channel

Oversimplified, my close second

History Time. His videos, especially the one on the Sea Peoples, is peak.

Dime Store Adventures is a guy who researches local history from around New England, travels there and makes videos about it. Often researching or trying to find something while filming, making it feel like an actual adventure. A lot of it is centered around cemeteries, background stories about the people buried there, grave monuments with crazy backstories, but also old newspaper articles, local legends and forgotten historical landmarks or geographical features. He seems pretty serious about doing his research, he clearly knows his way around local libraries and archives and I find his way of presenting the information and his enthusiasm about the subjects very engaging. Especially when he goes around looking for something and actually finds it.

What on Earth is This? Is a British guy who travels mostly around Europe (sometimes further) and goes to see engineering features or other manmade structures that have interesting backstories or stand out in some way. He tries to do a pretty deep dive into why something was built or operated a certain way while keeping his videos short and to the point. I also really like his enthusiasm and way of explaining things.

There's a million great recommendations in this thread already so I don't feel the need to add, but I wanted to chime in that the type of channel that would just use AI slides/"footage" today was always around but were just doing lazy work instead. Also a rule of thumb that seems to kinda work so far is if it's also on Nebula then it's usually pretty well made and researched.

Kyle Hill, Kurzgesagt - In a nutshell (they have channels in many languages) and fern come to mind

Folding Ideas is a favorite for me. His stuff is professional, entertaining, and educational.

Scotty Kilmer, ChrisFix and Project Farm for cars.

Philosophy Tube.

Lindybeige.

Exercise - Chloe Ting, Move with Nicole, Yoga with Adrienne.

Viva Longevity has become one of my favorite channels for anything nutrition and longevity related. Chris MacAskill is a retired Earth scientist who started the channel as a passion project. He claims to keep all possible ad things shut off, doesn't accept donations, and is doing the channel out of his own pocket.

The gist of it is to push back against all the misinformation, by providing a platform for the most cited and respected health and nutritional researchers, who do actual science, to talk about their work. He also has episodes about how industry-funded disinformation campaigns work to undermine the scientific communities.

Curious Archive is really good if you’re into media and story analysis and exploration. I’ve also been hooked on KBash for deep dive video game retrospectives.

Gamers Nexus has lately turned into a full blown journalist team. Their stuff is top notch, and it's powered by gamers not billionares.

Reject Convenience and their side channel, Privacy Policies Explained.

I mean, the easiest way would be to go for organizations over individuals...

Like PBS, or https://www.youtube.com/@TheInstituteOfArtAndIdeas/videos

If you're just watching random videos, there's gonna be a bunch of slop

If you’re on a browser, I’d recommend:

https://github.com/amitbl/blocktube

And perhaps other YouTube client apps have a similar feature.

I find, for a given topic, that there are a few common channels spamming hundreds and hundreds of junk videos. Block them as you find them, and it cleans up the feed immensely.

It’s absolutely mind boggling that YT doesn’t include this as a default feature.

Also, respectfully I would not get too invested in YT.

The other day, I found my TV (with the stock app) auto skipping sponsers. That’s just one of a bazillion ways Google is crushing creators that make anything but attention slop, intentionally, so that kind of long-form content you like may not last.