"Of the Valar" in the Valaquenta) the following:
"whether of the Valar and the Maiar, or of any other order that Iluvatar
has sent into Ea"
Apparently there were additional "orders" of the Ainur besides Valar and
Maiar. This is not entirely surprising.
The Ainur correspond (more or less) to the Angels; and the
Angels traditionally (and for a Tridentine Catholic like Tolkien, definitely)
have been divided up into nine "orders": Cherubim, Seraphim, Thrones,
Dominions, Principalities, Powers, Virtues, Archangels, and Angels (in
descending order). So there's a lot more room for more orders than just
Valar and Maiar amongst the ranks of the Ainur.
Ungoliant (and Tom Bombadil too for that matter) could
belong to some other order besides Valar and
Maiar.
