Senate Majority Leader Chuck Schumer (D-NY) told ABC News Sunday that there have been a few other balloons that have been found over the United States and Canada. They were all smaller than the first one, he explained.
But as of Sunday afternoon, it was revealed that the FAA sent out a NOTAM shutting down air space over Lake Michigan for what they said was related to "national defense." The NOTAM is "a notice containing information essential to personnel concerned with flight operations but not known far enough in advance to be publicized by other means," the FAA explains on its website.
It hasn't been confirmed that this was another spying attempt by China, only the release of information about the restricted air space.
After the U.S. Air Force shot down the large balloon off the east coast of the U.S. the Pentagon said that the government had learned a great deal about spying at the hands of China's government. Since then, several balloons have been seen with two that have now been shot down.
There were several people who claimed to see objects flying over Lake Michigan, but their assessments of what they saw hasn't been confirmed. You can see those here.