Linen - perfect for brightening the eye area and hiding signs of fatigue. Pink and peach concealers are best to combat dark under eye circles.
Peach - to hide dark circles or other spots for those with medium to dark skin tones.  
Flax - to conceal purple or blue bruises, veins or under eye circles. Yellow concealers are the most versatile and are great for evening out skin tone and brightening complexions.  
Sweet Basil - to neutralize any redness due to acne, scarring, rosacea, windburn or sunburn. Green concealers significantly reduce redness and give foundation an even base.
Lavender - to eliminate any unwanted yellow undertones/spots on your skin. Purple concealers will brighten pasty, dull or yellow complexions.