The dark pattern I've noticed a few times is the exact match I type into Amazon search doesn't even return the item I entered but 2 or 3 entire pages of alternatives.

I know the item is there because Google returns it, either as a search response or in their "shopping" widget. I can click through Google to Amazon and see the item, sometimes even from the certified seller. But if I enter the exact search term in Amazon's search bar it doesn't show up in their own results.