Preheat your oven to 350°F (175°C).
Grease and flour a 9x5 inch loaf pan.
In a large bowl, combine the grated zucchini, sugar, and oil, mixing well.
Add the eggs and vanilla extract, stirring until fully incorporated.
In another bowl, whisk together the flour, baking soda, baking powder, salt, and cinnamon.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
If using, fold in the walnuts and raisins gently.
Pour the batter into the prepared loaf pan, smoothing the top.
Bake in the preheated oven for 50-60 minutes, or until a toothpick comes out clean.
Allow the bread to cool in the pan for 10 minutes before transferring to a wire rack to cool completely.