NFL Connections #63, Answers
The full solution: all four groups and the 16 names, sorted from the easiest group to the trickiest.
Today's sack artists
T.J. Watt, Myles Garrett, Aaron Donald, Cameron Jordan
2000s pass rushers
Dwight Freeney, Jared Allen, Julius Peppers, DeMarcus Ware
1990s pass rushers
Reggie White, Bruce Smith, Kevin Greene, Chris Doleman
Classic-era pass rushers
Deacon Jones, Gino Marchetti, Jack Youngblood, Carl Eller