The cream sauce I use is always changing just a bit. The basic ingredients are:
½ cup yogurt
a squeeze of mayonnaise (for me, I use just a little as I am not a big mayo fan)
a couple of cloves of garlic (around 5/6)
Juice of a Lemon or Lime (can also use zest )
Salt and Pepper
Blend all these together in a magic bullet or blender until smooth. You might need to add just a little water or more juice if the mixture is not blending well.
At this point, I taste and adjust the seasoning.
This gives me the base for this sauce. I add herbs like cilantro, basil, or chives. Other ideas are onion, cucumber (salt and drain before adding), hot sauce, honey or anything that sounds good to me at the time. When adding new ingredients that I have never used in this, I add them slowly and blend. Taste to see if I want more of that flavor not. Adjust as needed.