It wasn't that long ago when the only eyeliner I had was black in colour and it was unfathomable to have it in any other colour. Today, any major cosmetic label will stock eyeliners and mascaras in a myriad of colours.
Black, the traditional choice. It clearly defines the eyes and creates a dramatic effect. Popular choice amongst women and you really can't beat the classics. Middle Eastern women have been using khol for centuries.
Brown, eyebrow or eyeliner pen. It's a more discreet colour to use when defining eyebrows and eyes, creating a natural look popularized by Bobby Brown. I use brown eyeliners everyday (Calvin Klein Brunette), to work or running errands. It's soo non-intrusive and subtle, you look better but it's not obvious you are wearing makeup.
Blue, ranges from light turquoise to dark midnight blue. My new favourite is a navy blue (Dior Captivating Blue)! Blue eyes and red lips always create a stunning visual and is kinda dressy that might be too much for everyday wear. I find using blue eyeliners instead of eyeshadow help translate this look into everyday wear. You can top up with eyeshadow for evenings out.
Rouge, ranges from peach to red. The first coloured eyeliner I bought was a rouge (Shu Uemura Me Wine). This creates a "wayang" look and if you line your entire eye with it without putting on anything else, it looks as though you've been crying the night before. Best used with eyeshadow.
White, the highlighter. White eyeliner creates as dramatic an effect as black eyeliner, making your eyes look bigger and brighter in the process. Can be used to create a bold winter look with cooler shades or to highlight a tanned face with ordinary makeup. I like to use it to line the sides and insides of my eyes to make it really pop (Lancome Blanc Audacity).
Shimmer, for the sparkle that all girls love. Self-explanatory, all girls will buy something shiny and find an occasion to wear it (Urban Decay Distortion).