All of them. Different ones behave in different ways, but none of them behave like finite numbers.

... but that's set theory, a step bigger than flipping the "finite" modifier.

What if I started with finite cardinals?

I think what we'd use for utility is like cardinal numbers, although that's not precisely what it is. There isn't a set of different QALYs. The finite values are more like real numbers. You still talk about how many QALYs, though.