Amazon Prime lets you choose a "Prime Day" and when you place an order, you can choose to have it be delivered on that day of the week. Not a perfect solution

Amazon Prime lets you choose a "Prime Day" and when you place an order, you can choose to have it be delivered on that day of the week. Not a perfect solution since sometimes orders come from different warehouses so are still packaged separately, but it's a pretty good way to combine orders into less packaging.