Is there anyway in the game to pickup the Boots of Displacement to finish off the Stormshroud armor set look wise? I tried looking on the BMAH but I’ve never seem them at all
Sadly, the only stuff from vanilla Naxx 40 that can show up on the BMAH is tier 3 pieces, not any of the non-tier stuff. Those boots won’t ever be available on the BMAH.
The only real hope of finishing sets like that is if Blizzard adds new items using those appearances. They did so during Legion and BfA for a few sets (in BfA we got the Dark Animator’s Set which added in some appearances that were previously removed from the game in Cataclysm).
So the best thing you can do is point out the stuff you want to see added and maybe Blizzard will add it as quest rewards, rare drops, or maybe even as a full ensemble from the Trial of Style. There’s an in-game suggestion submission option that serves well to tell Blizzard what you’re looking for.