Currently largest and most successful YouTuber on the platform (by a wide margin), started out by doing challenge videos about himself (24h in ice, that kinda stuff) that he'd invite friends to as the goody sidekicks causing mischief and making his challenges a little harder/more interesting.

These days, his stuff has transformed into a media powerhouse, all of it is still kinda falling into a challenge category. Now with far higher stakes and involving other people in competitions against each other - think "kids vs adults - group with most people still in the game after 5 days wins $500k" - where several days (sometimes months) of filming all gets cut down to one 10-20 minute long video.

There's also just "look at this thing" videos like "$1 to $10,000,00 car" where him and his friends check out increasingly expensive cars until they eventually get a whole bridge cordoned off to drive in the most expensive car in the world.

He does some philanthropy, like his "plant 10 million trees" campaign and makes money through sponsorship deals and advertising his own brands - they're currently running their own line of (fair trade?) chocolate bars that are available (in most places?) in the US, which kids will buy because of the brand recognition, leaving them with a ton of profits.