Preheat the oven to 375 degrees F.
Arrange the bread slices on 2 heavy baking sheets. Drizzle 3 tablespoons of olive oil over the bread slices. Bake until the crostini are pale golden and crisp, about 10 minutes.
Meanwhile, stir the herbs, lemon zest, pepper, and salt in a medium bowl to blend. Using about 2 teaspoons of cheese for each, form the goat cheese into 1-inch diameter balls. Roll the cheese balls in the herb mixture to coat completely. Arrange the cheese balls on a platter. Drizzle the extra-virgin olive oil over and around the cheese balls. Serve with the crostini. Garnish with herb sprigs.
The crostini and cheese balls can be prepared 1 day ahead. Store the crostini in an airtight container at room temperature. Cover and refrigerate the cheese balls.