The most significant outside addition made by the Pittsburgh Penguins this offseason was probably acquiring veteran forward Kevin Hayes from the St. Louis Blues in a salary dump trade.
Realistically speaking, the Penguins were probably more interested in the second-round pick they acquired as part of that deal, and Hayes was simply the cost it took to buy that selection.
Whatever the case, Hayes is now a Penguins for — presumably — the next two years at a very reduced salary cap number. A couple of years ago, Hayes would have been a nice player to have on your roster.