There is the greenpeace guide to fairer electronics:
But by placing apple on second place they kind of shot themselves in the knee and will never be taken seriously. See some discussion here:
Other than that as the CEO of Fairphone said it himself (I don’t have the exact quote at hand right now): “The fairest phone [even fairer than a Fairphone] is always the phone that doesn’t have to be produced anymore [=second hand phone]”.