You mean you didn't quote this?
"Halisstra opened her eyes and found herself drifting in an endless silver sea. Soft gray clouds moved slowly in the distance, while strange dark streaks twisted violently through the sky, anchored in ends so distant she couldn’t perceive them, their middle parts revolving angrily like pieces of string rolled between a child’s fingertips. She glanced down, wondering what supported her, and saw nothing but more of the strange pearly sky beneath her feet and all around her.
She drew in a sudden breath, surprised by the sight, and felt her lungs fill with something sweeter and perhaps a little more solid than air, but instead of gagging or drowning on the stuff she seemed perfectly acclimated to it. An electric thrill raced through her limbs as she found herself mesmerized by the simple act of respiration."
Which is an excerpt from Condemnation by Richard Baker, the Third Book in the War of the Spider Queen Series, which was reprinted as an excerpt, with full sourcing in the DMG?
Or, does that not count since they decided to put a quote from a book in the DMG, so it isn't actually quoting the novel, even though the only text you quoted was from the novel? (Spoiler alert, that isn't how quoting works, since you only quoted the text from Richard Baker's work, you were quoting him, otherwise I could say that I was quoting Alan Moore while quoting the passage from Percy Shelley's "Ozymandias" that Moore used in Watchmen, crediting Moore with a work that he did not write.)