He's not quite good enough and makes too much money IMO for a contender to want to package other parts to upgrade for (a la Tkachuk to Florida) and is definitely nowhere near a distressed enough asset for more of a pure cap move (PLD to Washington). NHL teams are also not bold enough to do a pure star-for-star trade that you'd probably hope for. That leaves basically just the non-playoff teams hoping to make it in. Think you're probably looking at something similar to the Sergachev deal in the summer, maybe a little bit more as I think Barzal's reputation is still higher than Sergachev's.
Barzal to Seattle for Wright, Gourde, and Burakovsky
Barzal to Buffalo for Cozens, choice of Kulich/Ostlund/Helenius, 25 1st
Barzal to Utah for Macelli, choice of But or Simashev, Hayton
Don't see any other fit really