It stands to reason (alike the VOY episode) that not all Voth are going to feel the same way, and that some would wish for an escape. Besides the fact, Cryptic seem to have gone to a lot of trouble with their design; it's rare for them to do so if they're just going to be NPC.
I am going to go against the grain and say it isn't going to be a Voth Lockbox but rather a Dyson Sphere lockbox, whose items will be a mix of Voth and Dyson tech.
As mentioned, probably a Voth ship or maybe another alien ship from the same race as the alien carrier.
We don't know much about the new warzone feature of Season 8, but I bet there will be some sort of special deployable consumables similar to the starbase fleet action consumables specifically for warzones, I would imagine some of those will be in the lockbox.
Probably a new console built from tech uncovered in the sphere.
As with everybody else I am hoping for Voth Boff (since a Boff captain race is probably out of the question, )