Vanilla: Use the base recipe, adding 1/2 tsp vanilla extract and a pinch of salt.
Tropical: Use 3 frozen bananas, 1/2 cup frozen mango, and 1/2 cup frozen pineapple. Instead of using milk to blend, add a splash of orange or pineapple juice.
Mocha: Use the base recipe, adding 2 Tbsp cocoa powder, 1 tsp instant coffee, and a handful of chocolate chips.
Strawberry: Use 3 frozen bananas and 1 cup frozen strawberries (or cherries!)
Raspberry Basil: Use 3 frozen bananas and 1 cup frozen raspberries, adding 1 Tbsp chopped fresh basil.