Personally I don't consider garlic powder or onion powder to be spices. They're both vegetables which have been industrially manipulated. I also wonder about capers ( which are usually used in pickled, or salted form - never seen them dried) and tamarind, which is a leguminous fruit. Indian cuisine, for example, uses dried mango powder ( amchoor) and dried pomegranate seeds ( anardana) for sour, but I've only ever seen tamarind in liquid form.