Well, if there's a Minus D, it stands to reason there's a Plus D...so at or around A would seem to be the starting point. Just what would that be?!
God-like beings, such as the Organians in their true form?
It seems a scale like that would have to be constantly
re-tooled to accommodate the new "energy" beings they encounter: Trelane's parents, the Day of the Dove
whirlygig, the Dikironium cloud, the Organians, the Thasians, the Metrons, the Lights of Zetar, "Jack the Ripper", Gorgon, Sargon & Co.,...an ever-growing list to be ever-updated so as to seem meaningless!