Moonlight is a very delicate silver micro fleck top coat, meant for layering over other polishes. It produces a subtle but beautiful silver sparkle effect.
Rather than offering sets, purchasing three or more bottles of polish from the Sun, Moon, and Stars collection in a single order will give a discount of 3.5% on all Sun, Moon, and Stars collection polishes in the order, which will be reflected in the cart under the line "Sun, Moon, and Stars collection discount."
The last photo shows what Starlight Polish 15mL and 7.5mL bottles look like.