Preheat the oven to 375℉. Grease a 12-cup muffin tin or 24-cup mini muffin tin. Alternatively, you can use muffin liners.
Mash bananas. Finely grate zucchini and carrots and squeeze as dry as possible.
Combine wet ingredients in large mixing bowl. Bananas, zucchini, carrots, eggs, milk, butter (or oil), vanilla and maple syrup.
Add in dry ingredients, flour, baking powder, baking soda and cinnamon. Stir gently until no lumps remain.
Gently fold in blueberries.
Divide batter in the muffin tin and bake for 23-25 minutes depending on your oven. (or 15-20 minutes for mini muffins)