Everyone in the NFC North anyway.
ESPN put together a list (lists!) of every NFL team’s biggest rival. When they circled around to the NFC North, the Green Bay Packers were listed as the biggest rival of every other team in the division.
And I guess, could you really argue?
The Packers and the Bears have the oldest rivalry in the NFL. They first met in 1921. It was noted — at least in the past — for great moments like this.
The Packers and the Lions have the oldest continuously-running rivalry in the NFL.