First, another important power reserved to the federal government is to create laws governing patents and copyrights. States may not grant copyrights or patents for any invention or work of art.
Second, the Tenth Amendment provides that powers not granted to the federal government nor prohibited to the states belong to the states belong to the states. So, the founding fathers contemplated that other kinds of powers could easily have been left out and the Constitution does not allow the federal government to assume those powers. They must go to the states. These include education and laws governing marriage and divorce.
Finally, I think it is worthy of mentioning the reasoning behind which powers are reserved to the federal government and which do not go to the states. In each and every instance, allowing states to have these powers would have led to us not being a true nation at all and would have had dire consequences from a purely practical point of view. Imagine what would happen, for example, if each state had its own postal system. You would need a stamp to get a letter from California to Arizona, another stamp to get it to New Mexico, and so on. For a letter to get from California to New York would have been burdensome at best. The same is true of a monetary system. Who wants to go from Pennsylvania to Ohio and have to go exchange to the local currency? In terms of treaties or warfare, it would not work very well for Maryland to have a treaty with Spain while Virginia declared war upon Spain. The founding fathers really thought this through, contemplating how this system would work out practically and how some kinds of powers must be national in order to have a true nation. It never ceases to amaze me how intelligently all of this was done.