<b>The Empire with tons of it's uber superweapons</b>
I doubt would be able to destroy the borg completely. The Empires superweapons were mostly threats. Combined with the fact the Borg have the transwarp conduit system and teleporters, Imperial weapons could quite possibly become Borg Weapons.
Death Star, Invaded by wave after wave of Borg Cubes and Sphere, being transported into, back and forth. Borg start to redesign the DS to their needs, taking apart technologies and adapting themselves to them. the Borg might lose all the Cubes they throw at them, but in the end, the DS would most likely be assimilated. As weve seen from their fight with species 8472, we know that the borg are relentless at sending cubes at unbeatable foes.
Same thing with the Sun Crusher, it enters a borg system, Borg intercept it, Sun crusher rams through a borg cube, Borg beam a couple drones into the SC. Pilot gets infected with nanobots. Might set the system to nova. In the end, the Borg have a SC still.
Galaxy Gun, destroy maybe two Borg worlds, Borg Track it down, board it or attach themselves to the outside of it. The galaxy gun falls to the Borg, wether they assimilate it or the Empire destroys to keep it out of their hands.
<b>The Yuuzhan Vong at their prime, which would be just before Star By Star</b>
The Vong.... Maybe.... MAYBE. They would be driven mad by their anti technology fervor. Im sure that would add a little to them as well. Their worldships would fall of course. I have no clue what the Borg would do with a living ship though. The klingons fell before the Borg though, so Im certain they could handle borg Drones. Not to mention once one fell, they would pretty much know enough about the Vong to come up with a counter attack method. I think the Vong and the Borg might just fight it to a stand still. Though, in the way were looking at it though, that might not happen till everyone else was wiped out, since the Vong would most likely be out killing everyone else too.
<b>The Yevetha</b>
No chance in hell, all dead in the first wave
<b>The Ssi-Ruuk</b>
Another no chance, the Ssi-Ruuvi would need to Entech a force user for long distance life sucking. They have yet to be able to entech a single force user of any power in the entire cannon.
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