NFL Connections #69, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
Manning-era Colts
Peyton Manning, Marvin Harrison, Reggie Wayne, Dallas Clark
Brady-era Patriots
Tom Brady, Rob Gronkowski, Julian Edelman, Wes Welker
Brees-era Saints
Drew Brees, Michael Thomas, Jimmy Graham, Marques Colston
Mahomes-era Chiefs
Patrick Mahomes, Travis Kelce, Tyreek Hill, Rashee Rice