NFL Connections #39, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
1970s Pittsburgh Steelers
Terry Bradshaw, Franco Harris, Lynn Swann, Joe Greene
1970s Dallas Cowboys
Roger Staubach, Tony Dorsett, Drew Pearson, Bob Lilly
1970s Oakland Raiders
Ken Stabler, Fred Biletnikoff, Art Shell, Gene Upshaw
1970s Minnesota Vikings
Fran Tarkenton, Alan Page, Carl Eller, Chuck Foreman