Topps regained the NFL football card contract in 1968. During the four years that Topps produced cards for the American Football League instead, the company only put out team cards in 1964. For 1968, Topps did a limited release of oversized test team cards in black and white, but they were not part of the regular set. At that point, team cards died.
Here are my custom card renderings of what Packer team cards could have looked like from 1968-72: