There are quite a few different varieties of purple potatoes around the world. Here are some of the favourites: Purple Peruvian, Toolangi Delight, Purple Majesty, All Blue, Royal Blue, Congo, Adirondack Blue, Purple Gem, Purple Fiesta, and Vitelotte. Most of these potatoes boast a deep purple flesh and don't always diminish in colour when put through the cooking process. Some of them have white streaks or patches on the purple flesh.