From experience, there are no items obtainable via the DNS exploit in Black 2 & White 2. I've performed the glitch dozens of times, and only received the same few Pokemon. While you can get the Liberty Pass Key Item in Black & White, you can't in the sequels.
There have been some people claiming they got the Secret Egg on BW2. However, this is not technically an item, as Eggs cannot be stored in the bag. I've also never personally gotten the Secret Egg on BW2, so these accounts are very likely misremembered or simply false.
Tl;dr there are no items from DNS in BW2.