When I started my weight loss journey, I used lemon juice, or balsamic vinegar, or even salsa! All of those are very low in calories and won't blow your diet.
I came across these little gems from Bolthouse farms in the refrigerator section of my produce department. SALAD DRESSING MADE WITH YOGURT! Thank you! They make creamy salad dressings made with yogurt at only 35-45 calories for 2 tablespoons. They have Classic Ranch, Salsa Ranch, Chunky Blue Cheese, Zesty French, Caesar Parmigiano, Thousand Island, Honey Mustard. I have only tried 2 of them, but I LOVE the Salsa Ranch! Try it!