Low carb veggies
Alfalfa, artichoke hearts, avocado, French beans, broccoli, cabbage, cauliflower, celery, celeriac, chicory, Chinese cabbage, chives, cos lettuce, cucumber, iceberg lettuce, bean sprouts, mushrooms, olives, onion, pak choi, parsley, peppers, radishes, rocket, spring onion, spinach, tomato, asparagus, aubergine, Brussels, courgette, leeks, mange tout, pumpkin, rhubarb, sauerkraut, and turnips.
All in moderation, check carbs of portion size to ensure you stay within limits.
Taken from Atkins book, all recommended for all phases of Atkins.