Either ROR or Timo Meier
ROR provides us an elite 3c with cup winning pedigree. He's a playoff monster and we can make him the matchup center against the likes of Kucherov/Point and Boston's top line. He already owns Marchand/Bergeron/Pastrnak lol
Meier gives us the physical, scoring power forward we've dreamed of. Come playoff time we've struggled with scoring goals and this is probably the best scorer you could get. It also gives us a lot of options for how we set the lineup. Do you want him on line 2 with Tavares/Marner? Do you want to run Matthews/Marner, Tavares/Meier and give Willy his own third line? The additional positive behind him is that he will be an RFA at the end of this year. So, even if we shell out assets for him we will still have his rights and can deal him somewhere for good value. Look at what Minnesota got for Fiala in a similar situation. This way, you may burn a first + something else to get him, but you'll end up recouping that value