Mirapoix is exempt from this, along with garlic. I think this could make for some interesting answers depending on the kitchen you are in. Sometimes we use things that just seem second nature to us, but we do not really realize how much of it we actually use. This will vary hugely for ethnic cuisines and I am excited to hear about it. For us, it is shallots. They seem to go in everything, vinaigrette's, sauces, salads, etc... We just always have them around.