NFL Connections #50, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
Hall of Fame receivers (classic)
Don Hutson, Raymond Berry, Lance Alworth, Paul Warfield
Hall of Fame receivers (modern)
Marvin Harrison, Isaac Bruce, Tim Brown, Andre Reed
Hall of Fame tight ends
Tony Gonzalez, Shannon Sharpe, Kellen Winslow, Ozzie Newsome
Hall of Fame quarterbacks (classic)
Johnny Unitas, Bart Starr, Sammy Baugh, Otto Graham