Preheat oven to 350. Prepare a 9x5 bread loaf pan by either lightly greasing with coconut oil or lining with parchment paper. If using parchment, cut a piece that is as wide as the loaf pan and place parchment on the bottom and up the short sides. This allows you to easily pull on the parchment to remove the bread from the pan when done.
Using a few paper towels, squeeze as much excess water from the grated zucchini as you can. You may need to repeat a few times with dry paper towels. Set aside.
In a large mixing bowl, combine the gluten-free flour, almond flour, tapioca starch, cinnamon, nutmeg, baking powder, baking soda, and salt.
In a separate bowl, combine the mashed banana, coconut oil, coconut sugar, eggs, vanilla, and grated zucchini. (tip: mix the banana, oil, and sugar together first before adding remaining ingredients; this will help the coconut oil from solidifying when the cold eggs are added).
Add the wet ingredients to the flour mixture and stir until fully combine. Batter will be on the thicker side.
Scoop batter into prepared loaf pan. Spread batter evenly through pan.
Bake for 45-55 minutes, or until a knife inserted in center of bread comes out clean. I usually check the bread at about 40 minutes and if it looks like it's starting to brown too much on the top I will tent with a piece of foil.
Let cool 5-10 minutes before removing from pan. Pull on parchment paper to remove. If needed, run a knife along the long sides of the pan to loosen bread.
Slice and enjoy!