For me it was Tanelorn by Blind Guardian. Hair metal in my head, all afternoon.
Sure Zoroastrianism had it's impact ('tho I'd argue that had bigger impact on Tolkein -- "keeper of the sacred flame" and all that) but I'd also throw out Chaos, the first god, as an influence:
https://en.wikipedia.org/wiki/Chaos_(cosmogony)
If you listen to any interviews with Moorcock he'll list influences all day -- his modesty is one of his better traits.
There are really no direct influences of Zoroastrianism in Tolkien. Sacred flame is hardly a unique concept to that religion. Tolkien has a mix of elements from Norse mythology, but his biggest single influence was his own Catholicism. The Judeo-Christian God exists in Tolkien’s Middleearth, Sauron is a lieutenant of Satan, the wizards are angels and the struggle between good and evil is distinctly Christian. This isn’t even speculation, he wrote all of this in letters.
And Greek chaos doesn’t have much to do with modern conceptions of chaos. It’s more of a primordial void than the jumbled opposite of order. That idea came later. Greeks thought on terms of civilization versus wilderness / savagery, reason versus irrationally, and masculine versus feminine (the Greeks at large had pretty poor opinions of women), and the way they conceived these could all be considered expressions analogous to our contemporary notions of law and chaos, but that had little to do with their version of chaos.
