NFL Connections #91, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
Washington quarterbacks
Joe Theismann, Doug Williams, Kirk Cousins, Jayden Daniels
Washington running backs
John Riggins, Stephen Davis, Larry Brown, Brian Mitchell
Washington pass catchers
Art Monk, Gary Clark, Santana Moss, Terry McLaurin
Washington defensive legends
Darrell Green, Sean Taylor, Dexter Manley, London Fletcher