NFL Connections #97, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
All-time great QBs
Tom Brady, Joe Montana, Peyton Manning, Johnny Unitas
All-time great running backs
Jim Brown, Barry Sanders, Walter Payton, Emmitt Smith
All-time great receivers
Jerry Rice, Randy Moss, Terrell Owens, Calvin Johnson
All-time great defenders
Lawrence Taylor, Reggie White, Deion Sanders, Ray Lewis