He's like a younger version of Applied Science: https://www.youtube.com/c/AppliedScience

I also consider the likes of

Bismuth https://www.youtube.com/c/Bismuth9 and

SummoningSalt https://www.youtube.com/c/SummoningSalt

to be intellectual in the deep dive historian type of way.

LPL has already been linked: https://www.youtube.com/c/lockpickinglawyer

I used to follow NightHawkInLight but his content has slowed recently: https://www.youtube.com/c/Nighthawkinlight

Matt Parker is awesome (I have his book, too): https://www.youtube.com/user/standupmaths

He appears often on: https://www.youtube.com/c/numberphile