Is there a good salad dressing that does not include vinegar?

Between honey mustard and ranch, you save 6 grams of fat in a 2tbs serving. That said, the obvious answer all around is don't use 2 freaking tablespoons of dressing. That's 1/8 of a cup or 2 big goob fulls of soup. You only need a light coating of dressing which will vary per the size of your salad. The average home bowl will only need a pea sized drop, not 2 tablespoons. At that point, you save 10.8 grams of fat in ranch dressing.  

You could use lemon juice, and some dressings don't have ANY acid in them, but they are milk-based.

If you are making the salad dressing replace mayo with Greek Style Yogurt.  That will cut some of the fat. And you could even use a 0 fat yogurt. 

Salad dressing does contain a high % of fat and the vinegar is needed.  You could replace vinegar with lemon juice if you want to reduce the acid level a bit or you could try a different type of vinegar like a Rice Vinegar or a Sherry Vinegar. Both are milder than regular white vinegar. 

Almost all dressing have a high percent of Fat - that is what dressings are oil, acid, flavorings. If Balsamic isn't too objective (a good one is pretty mild) just use a dash of it on salads and skip the fat entirely.  Mix balsamic with a little dijon and some spices for other options - we make Italian dressing using the little packets and balsamic - but of course evoo (fat) but you could skip the oil and just have watery dressing. 

Caesar doesn't include vinegar.   It gets it's acid from lemon juice.  

You can make pretty much any salad dressing with lemon juice instead of vinegar.

If you don't miss the acid, you could just use some herb infused oil.

Have you tried different types of vinegars?   Many people find cheap red wine vinegar especially acidic but can tolerate apple cider vinegar or a good quality balsamic.

ETA:  To the person that suggested ketchup and relish...both are loaded with vinegar.  

Ketchup and mayo-instant French dressing. Add some relish and you have Thousand Island dressing.