NFL Connections #44, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
1990s Dallas Cowboys
Troy Aikman, Emmitt Smith, Michael Irvin, Deion Sanders
1990s Buffalo Bills
Jim Kelly, Thurman Thomas, Bruce Smith, Cornelius Bennett
1990s Green Bay Packers
Brett Favre, Reggie White, LeRoy Butler, Sterling Sharpe
1990s Denver Broncos
John Elway, Terrell Davis, Shannon Sharpe, Rod Smith