Luxirare made a set of edible crayons, each with a recipe based on the available ingredients' colors. Yum!
The purple and blue are least healthy, they have more candy and sugar in them haha. The purple one used freeze dried blueberries (also such a good snack, and good for making jams or blueberry sauces without buying fresh blueberries, these keep for such a long time!) and the blue used dried blueberries (different texture than freeze dried, it has more of a chewy and wet mouthfeel).