Best trade No. 3 - Duane Brown (2017)
The Seahawks traded a 2018 third-round and 2019 second-round picks to the Houston Texans for Duane Brown and a fifth-round choice in 2018.
Duane Brown might arguably be the second-best left tackle in Seahawks history. He's no Walter Jones, of course, but Brown has a decent chance of making the Pro Football Hall of Fame one day. He spent 10 years with Houston before coming to Seattle so he will likely be better remembered as being a Texan, but he still made the Pro Bowl twice in five years with the Seahawks.
He didn't make the Pro Bowl in 2018, but he was named second-team All-Pro and that's probably a better mark of his excellence. That year he allowed only 2 quarterback hits and 21 total pressures. In 2019, Brown allowed just 1 sack and 2 quarterback hits. In an elite-level 2020, he had just two penalties and allowed 5 quarterback hits and 2 sacks. He was a fantastic left tackle for Seattle.
The draft picks Seattle gave to Houston for Brown turned out to be Martinas Rankin and Lonnie Johnson. Johnson played three years for Houston and left after 2021. Rankin has been out of the league since 2020. Seattle chose Shaquem Griffin with the pick they got from the Texans.