I used to put sour cream on everything! I still do, but I had to find a dairy-free one and I'm very impressed with Tofutti brand, Sour Supreme-Better Than Sour Cream. It tastes remarkably like sour cream. I was searching for recipes to make my own, but came across this instead and have been very pleased.

They also make a cream cheese that dairy-free and tastes very much like dairy cream cheese.