Drifter sells the Bygones pulse rifle, Trust hand cannon, and Bad Omens rocket launcher, which can be equipped at the same time to earn the "Dark Age Arsenal" Triumph required for the Dredgen Title. You may need to reset your Infamy rank several times in order to unlock all of these vendor purchases.
Night Watch/Lonesome Gnawing Hunger Bad Omens. I think these are the only weapons that aren’t sunset yet. That I think count as Gambit. Plus the new 120 Handcannon maybe.