Yes. Purple is not commonly seen in the world of Avatar as it does not represent any of the four elements. However, many characters have been shown wearing a shade of purple throughout the series. For example, Princess Yue's lighter clothing is shown as a long dress with a purple tint to it. Furthermore, King Bumi wears a green or purple robe as the King of Omashu. The citizens of Jang Hui wear many variations of the color purple. Lastly, members of the Order of the White Lotus wear uniforms consisting of indigo robes and capes.