Sure! The sky is the limit here. Choose your favorite ice creams and toppings and mix them up however you'd like. Just remember that everything that goes in the cake will be frozen. Anything that might not work well in the freezer can be added when you serve the cake. For example, don't put chocolate chips inside the cake because they'll be too hard when frozen. Fruit, like fresh strawberries or raspberries, should be added when serving and not put inside the cake layers.