I love nuts! So you could try different chopped nuts-- I am thinking you may not be able to use granola due to the carbs. I make my own granola, and it is always good in yogurt. The sweetener I'd suggest also the Stevia. Extracts can be overpowering, so I too would recommend the vanilla or almond. I would use these when flavoring ricotta cheese for a mock ice cream when on South Beach Diet. Cinnamon might also be a possibility. You could also try banana. Fruit dips with yogurt lime juice, and stevia are good. Fruit smoothies with fresh or frozen fruit, yogurt, stevia, and protein powder are good. You can add spinach or baby kale to the smoothie as well. Frozen drinks like fruit smoothies seem to want more sweetness to taste it in my opinion.
greek yogurt is very popular, but I find it very sour, especially without sweetness.