The idea of a single "best" liner shade for your eye color is a very outdated notion, but certain shades can intensify your natural eye color and its good to know which ones do.
Rich golds and coppers will make blue eyes appear even bluer, whilst greys will really lighten up cool blue eyes.
Rich intense purples will make the eyes appear greener and soft golden bronze tones look beautiful on green eyes.
Midnight blue tones and warm earthy toned browns will emphasize the light flecks in brown eyes.
Golden metallic olive green will bring out the green tones in hazel eyes whilst warm, neutral browns enhance their multi toned richness.