Preheat an oven to 350 degrees F (175 degrees C). Grease baking sheets.
Stir together the flour, baking soda, cinnamon, and cloves in a bowl; set aside. Beat the butter and brown sugar with an electric mixer in a large bowl until creamy.
Add the egg and the vanilla extract.
Mix in the flour mixture and oats until just incorporated.
Wring the zucchini in a clean towel to remove any excess moisture. Stir the zucchini and raisins into the dough; mixing just enough to evenly combine. Drop batter by rounded teaspoonfuls 2-inches apart onto the prepared baking sheets.
Bake for 14 to 16 minutes or until the bottom edges turn golden brown.