Hm, that's odd. I always find these types of rare, unknown items intriguing. Once I traveled to the deepest section of a cave and found an empty Skooma bottle on a table and the item was titled "Empty Hist Bottle". It was quite random where I had found it and it has no real usefulness to my knowledge. It is listed on the
Miscellaneous Items page on the UESP, so I suppose it's not completely "unknown", but it was still quite an interesting find to me when I first discovered it. The Discarded Daedric Blood that you found is certainly more interesting, though, since it can't even be found on the UESP. I've personally never encountered it.