What besides carrots, celery, and iceberg lettuce are healthy, minimal calorie snacks? Any other suggestions?

Stop!!!! Hi, please do not overload on low calorie snacks. That doesn't work! lots of low cal carbs are digested rather quickly; leaving you hungry so stop. By eating less food you will shrink your stomach in a way, so consider a higher protein, lowish carb , low-mod fat eating plan. You will feel more full, less hungry, more satisfied; therefore less likely to want to eat more calorie laden food!
Healthful snacks. Others include raw broccoli, cauliflower, bell peppers, asparagus (thin, young shoots), small amounts of nuts like almonds, pistachios, walnuts.