They kind of vary. He has some goofy ones like extreme hide and seek with his friends / other youtubers. Last to leave the circle wins a prize. I ran a used car dealership where all the cars are free etc.
Almost all his videos involve giving away a prize to the contestants in the video or straight up charity. If the kind of video sounds familiar lots of people are copying trying to follow his lead to fame.
People can bash him but Mr Best seems like a genuinely nice dude.
The issue is this kind of "charity" is just trying to slap a bandaid on a bursting artery. Not to mention philanthropy in general is a pretty morally grey concept (because capitalism sucks and doesn't work)
I think he has the most popular youtube channel (or at least for english). The basic gist is him giving away absurds amount of money or expensive things for a silly task. Like going to the store and buying anything that the contestant can fit in a triangle.
Giving away money so he can monetise the videos and make more money, which he gives away, monetising those videos to make even more money. The guy has literally found a way to print money.