Most of these items have already been touched upon by other answers to this question, but I would highlight the following aspects of the Indus Valley civilization as distinctive:
The relatively large numbers of cities — there are about a thousand known sites associated with the Indus Valley civilization (cf. McIntosh, Jane R., 2008, The Ancient Indus Valley : New Perspectives, Santa Barbara, California: ABC-CLIO). Not all of these sites are as large has Harappa or Mohenjo-Daro, but there is no question that many cities of significance were interacting in this civilization cluster.
The relative lack of monumental architecture — although many of the Indus Valley civilization cities were quite extensive, covering a significant area (Mohenjo-Daro covered 250 ha or 620 acres), they did not build tall civic or ceremonial structures that would have poked up out of the ground like the pyramids of Egypt or the ziggurats of Mesopotamia. As a result, once the cities were abandoned and covered over, the civilization was lost to historical memory until rediscovered.
The relative peaceful character of the civilization — despite the large number of semi-independent cities interacting within the Indus Valley civilization, there was very little war, and what war there was took place on a far smaller scale than seen elsewhere in the world’s pristine civilizations. (Cf., for a popular treatment, The real utopia: This ancient civilisation thrived without war)
While all ancient civilizations engaged in agriculture and animal husbandry, the particular cultivars and animals are distinctive in each case. The Indus Valley civilization cultivated cotton, bananas, date palms, mustard, sesame, Oryza sativa (aka Asian rice), and at least three three species of wheat, Triticum aestivum (bread wheat), Triticum durum (macaroni wheat), and Triticum dicoccum (Emmer or Khapli). (Cf. Indian Institute of Wheat & Barley Research) Domesticated animals included humped and shorthorn cattle, domestic fowl, pigs, camels, and buffalo. Because each civilization possessed distinctive cultivars raised under distinctive conditions, the traditional foods unique to a region, and the traditional clothing woven from fibers of cultivars that are unique to a given civilization, all emerge from this original agricultural context.