Preheat oven to 325 degrees F (165 degrees C). Grease two 5x7-inch loaf pans. Combine butter and sugar in a large bowl; beat with an electric mixer until creamy. Add eggs; beat until lightly fluffy. Beat in bananas, papaya, raisins, walnuts, and crystallized ginger until batter is smooth. Sift flour, baking soda, salt, cinnamon, allspice, ginger, and baking powder together in a separate bowl. Mix gradually into the batter. Pour batter into the prepared pans. Bake in the preheated oven until a toothpick inserted into the center comes out clean, about 50 minutes. Cool in the pans for 10 minutes. Invert onto a wire rack to cool completely.