I don't have anything I keep "secret", per se, but a lot of things most people I know don't have in their kitchens! Besides all those already mentioned, here's something with a unique flavor, that I discovered in my early days of cooking, when I joined a co-op, down at school - some rice vinegar. That has that flavor, plus slightly less acidic that other vinegars - only 4%. That was what I use some in to make mayonnaise, which is the only way I'll eat anything with mayo in it. Later, I discovered the Chinese Chenkiang Black Vinegar - a rice and other vinegars, which gives a delicious and unique flavor to many soups and dip sauces - just not the same with other vinegars.