Your choice of: handlebar grips lockrings, bar ends, seatpost clamp, saddle, stem spacers, break/shifter cable housing (only brake cable housing for example, not all 4 cables), chainring bolts, RD pulley, bottle cages, tires... Just chose a color scheme that you like a do it tastefully...

My personal preference goes to smaller details such as seatpost clamp, grip lockrings, RD pulley and cable housing possibly matching the color scheme found on the tires (how about wine red?).