There is the Borg-set which has 4 parts. 1 part you get as a reward for the mission Assimilated. The other 3 you get as a reward for the 3 STFs Infected/Cure/Khitomer Accord.
If you are prepared to wait for ages to get a team togther,then do the mission that takes the odd two hours to complete. I'm not sure if its worth the effert as i dont really see it much better then agis set. Tried both on tribble but cant see much,saying that i still want to get the full borg kit,is there any good chat channels anyone can recomend ???