Colors that are created by combining blue and yellow, such as green, complement peach because they are on the opposite site of the color wheel. White and black, although not technically true colors, also complement peach.
Peach is made by combining red and yellow. For this reason, the colors on the opposite side of the color wheel from red and yellow are those that naturally and most appropriately complement peach. Black and white also work inasmuch as they are generally considered neutral and capable of complementing nearly any true color, with white being considered a bit more versatile than black.