I thought of the obvious, fruit salad, yellow cantaloup or mango, red watermelon, strawberries or raspberries, blueberries, kiwis, oranges or clementine. and purple dyed mini marshmallows
![Laughing :lol:](./images/smilies/icon_lol.gif)
or purple grapes.
With Nancy's idea you can also use purple potatoes or cauliflower, even red onions are often more purple than red. There are always blue corn chips. I wonder if a few blueberries would turn water blue to dye potatoes?