I've heard some of those sugar-free dressings are kinda nasty. I bought some stuff today that is delicious! It's Bolthouse Farms brand Creamy Yogurt Classic Ranch. Found it by the salad greens in the refrigerated section. Ingredients: buttermilk, soybean oil, yogurt, apple juice, distilled vinegar, salt, egg yolk, natural flavor, xanthan gum, spice, onion, garlic. Gluten free. 70 calories per 2 Tbsp serving (which is pretty darn good also!)
This brand has other creamy yogurt dressings also -- 1000 Island, Bleu Cheese, Caesar, Italian and Cole Slaw but I didn't check the labels on them for sure. The whole line advertises no added sugars, so I think those might be P3-friendly as well. Anyway...thought I'd share!