Not one of the most important pieces of evidence against intelligent design, but maybe the one I think about the most frequently, is lead. It's wild that there's a substance that's incredibly easy to obtain even at rudimentary levels of technological development and incredibly easy to work with and incredibly useful for a huge range of purposes and it also poisons and kills you but very slowly! And this is only relevant to humans because other animals can't smelt ore. God's buck wild for this one
Put it glass, it makes it better. Put it on ceramics, it makes them better. Put it in paint, it makes it better. Put it in gasoline, it makes it better. Put it on your roof. Put it in your water pipes so much to where you name the entire concept of "plumbing" after it. But watch out lol
