Yeah, never heard of Mr. Beast as well, I only watch very specific YT channels, but after looking it up - yeah, those are insane numbers, in hundreds of millions of views.
That said, my answer is somewhat of the cheating, but here it is - Timothy Cain. He is creator (along with Leonard Boyarsky, Jason Anderson and others) of Fallout, and on several occasions he had videos about some of his ideas for several games. Well, I'd really like to see some of those games come into fruition.