Guild Wars 2

Back then I did not know what weapons to get, I already picked the warhorn, shield and sword.

But I still have two sets. So is there a chance to get a vendor so we can buy the weapon designs?

I will just bump this in case anyone @ Anet sees it and can either confirm or say no.

Dont bother posting a reply unless you have a valid source to an answer.

The vendor will likely return once Super Adventure Box itself returns, which it has been confirmed to do so at some point in the future:
https://forum-en.gw2archive.eu/forum/game/gw2/Super-Adventure-Box-merged-1/page/14#post4456748

There is little else that anyone or a developer can add than that, so just hope that it might be re-released sooner than we would expect.