Scrolling through my subscribes, here are some of the ones mostly widely interesting I figure. In no particular order:

Civvie11- Retro gaming enthusiast.

Beware The Qu- Lots of speculative evolution content.

Big red 40TECH- Battletech lore guy.

BobbyBroccoli- Long videos about science scandals.

Mandaloregaming- Long form game reviews.

Seth Skorkowsky- Videos about TTRPG reviews and how to run TTRPGs.

Warlockracy- Russian video game reviewer with a bent to older games and weird Russian obscure mods.

Forgotten Weapons- Man on a life's quest to collect French ammunition.

Red Letter Media- Movie reviews and such.

Wargamer Fritz- Battletech tabletop tactics.

ReligionForBreakfast- Scholar who talks about religious history topics.

The Tank Museum- Tanks.

The Chieftain- Tanks.

Paper Skies- Channel on strange aviation stories, focus on Soviet military aviation.

Quinn's Ideas- Scifi review channel. Huge Dune nerd.

Olden Demon- Oldhammer channel. Talks about 2e and retells old 2e official battle reports.

oboeshoesgames- Like Dunkey but still funny.

Minisodes- Plays Oldhammer 2e in modern day and paints retro minis.

Grim Beard- Goth that reviews usually more obscure games.

Billiam- Watches and reviews a lot of trash TV.

Ancient Americas- History channel about ancient American (north, central, and south) history.

I'm subscribed to a lot of painting, DIY, instructional, and such channels which I find good but are very niche.