Line a bowl with a triple layer of paper towels. Grate the zucchini and place it in the bowl with the paper towels. Use the paper towels to squeeze as much liquid as possible from the shredded zucchini. (If the paper towels soak through and begin to tear, repeat with fresh paper towels, as needed.)
Discard the liquid and place a clean paper towel in the bowl. Transfer the squeezed zucchini to the bowl with the dry paper towel and let it rest for a few minutes.
Combine the flour, garlic, salt and pepper in a large mixing bowl. Whisk to combine. Add the eggs and whisk again. Add the drained zucchini, corn, and green onions. Stir to combine.
Heat about 2 tablespoons of oil in a large nonstick skillet over medium heat. When the oil is hot, scoop golfball sized scoops of the zucchini fritter mixture into the oil. (Approximately 3 tablespoons worth for each fritter.) Cook until golden brown, about 2 minutes. Flip them over and cook for 2 minutes more.
Transfer the fritters to a paper towel lined plate and repeat the process with the remaining oil and batter. Serve warm with sour cream, bang bang sauce, ranch dip, or marinara sauce.