Also potassium! And pretty much any high atomic number element.
EDIT: why is there so much lead? You wouldn't think there would be more lead than gold in the world....well, I mean, uranium decays into it, but still. you wouldn't think there'd be THAT much lead.
EDIT2: also, looking at the relative abundance of elements in the crust, Minecraft has HORRIBLE relative abundances. I mean, the Tower of Pimps alone contains more gold than exists on earth. And Mekanism puts osmium in the game, which is the rarest of all metals. But they made it more common than gold, and at its layers, more common than iron