Galactic Cluster 8 was the Borg designation for a region of space where they encountered Species 5973, multispectrum particle lifeforms.
When being told by Neelix of the USS Voyager's encounter with an unknown, gaseous lifeform in 2376, Azan guessed that it was a member of Species 5973, although this was denied by Neelix. (VOY: "The Haunting of Deck Twelve")