No actual idea. The only confirmation we has is he makes some commercials without his face in them (meaning we don't even know which ones they are), but if you look at the size of his crew and background work area its very clear they do more than just his videos. Shit he got a few guys from Industrial Light and Magic that he named in one video, which means he has connections too.

I honestly think if other youtubers used him they'd credit it, as he is a huge name in that sphere, and we haven't seen that at all. So they must be used elsewhere.