The DKNY Lurex Tank Dress.
This was given out to celebrate the new year and now cannot be sold in the StarBazaar - you used to be able to sell it for starcoins, but now you can't. I don't have this dress, although I would like to, but it is not incredibly rare and I think this is because it was originally given out for free.
DKNY Bike.
This was a prize for a competition on Stardoll in 2008. This is very rare even though it was free, and only a few were given out. Apparently, the bike was released after for 12sd - odd.
DKNY Interior (not technically free, but still).
The DKNY interior that a few users own was given out as part of the gift-o-meter that made an appearance on Stardoll at the same time as the anniversary collection - the sixth. When you spent 100sd you got the DKNY dress, and when you spent 200sd you got the DKNY logo interior.
The 5th DKNY collection.
This was released by accident for free for a short period of time before it was removed and released again for the correct price. I wish I had been there to buy everything!