I know of Robert Miles, and Writer, who does Rational Animations. (In fact Robert Miles' channel is the primary reason I discovered LessWrong :) )

There's also lsusr, who started posting videos recently.

https://youtube.com/@THUNKShow is pretty LessWrong

My friend Jackson Wagner had a nice technoliterate overview of Chrono Trigger: Six perspectives on free will, human choice, and the shape of history. I thought it was pretty touching.

Cadenza Labs has some video explainers on interpretability-related concepts: https://www.youtube.com/@CadenzaLabs

For example, an intro to Causal Scrubbing:

It might interest you to know that Kurzgesagt recently learned that they are the type of people who would read lesswrong, and have done videos on ideas like Grabby Aliens, and have taken commissions from OpenPhil.
But they arrived at the creed independently. I dug into the sources for their video on accelerating cosmological expansion and found no overlap with the sources of Ord's paper on accelerating expansion. I've also never heard of the ancient life hypothesis around our parts, despite that being the kind of thing we'd be into. So it's possible that they just have access to some higher quality idea-brokers than lesswrong and aren't really going to end up hanging out here x]

A recent interview I gave: 

And a more technical talk I gave at VAISU: 

@unoptimal Has a channel: https://www.youtube.com/@unoptimal/videos

Although not all of it seems to be rationality focused.

This is one of my favorite videos: 

I am producing videos in French (new batch in progress) on my main channel, Suboptimal.

But I also have a side channel in English, Suboptimal Voice, where I do readings of rationalist-sphere content. Some may appear in the future, I received requests for dramatic readings.