NFL Connections #76, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
Chicago Bears
Walter Payton, Mike Singletary, Brian Urlacher, Devin Hester
Green Bay Packers
Bart Starr, Brett Favre, Aaron Rodgers, Reggie White
Minnesota Vikings
Cris Carter, John Randle, Jared Allen, Justin Jefferson
Detroit Lions
Barry Sanders, Calvin Johnson, Lem Barney, Amon-Ra St. Brown