I believe
@baimun had posted a pic of a Harmony earlier. I think all that’s left, not mentioned, is Gold Tone, Heritage, Jackson, Journey, Kramer, Lakland, Larrivee, Loog, Peavey, Recording King, Reverend, Rickenbacher, Schecter, Sire, Squier, Steinberger, Sterling, Strandberg, Suhr, Traveler, Washburn and Xotic.
It’s probably not another Reverend. It must be a Suhr, because, who wouldn't want one?
Unless I've missed something, we've guessed all the brands Sweetwater currently carries. But, they do have an online market where customers can sell used guitars.