Dean Koontz's Phantoms will often include the descriptions of mundane sounds to help ratchet the tension, especially after some of the bodies have been discovered. Even though you're technically not hearing the sounds, the reader's own imagination is used against them with frightening results. This culminates later on when someone picks up the phone and starts hearing various mundane animal noises, which slowly turn into the sound of thousands of people screaming in hellish agony.
H.P. Lovecraft made extensive use of this one. Of particular note:
The "tekeli-li?" sound made by the shoggoths in At The Mountains of Madness. The narrator speculates that it may be a word in the language of the Elder Things, and the shoggoths are mindlessly parroting it.
It's the sound the birds make in EdgarAllanPoe's unfinished The Tale of Arthur Gordon Pym. ATMOM is based thereon.
The dripping sound in Cool Air, when Dr. Munoz' air conditioning stops working...
The gurgling sound on the telephone line in The Thing on the Doorstep
And the recurring cries of "I?I? Phn'glui mgl'wnafh Cthulhu R'lyeh wgah'nagl fhtagn!"
The creepiest idea August Derleth came up with in his questionable additions to the Cthulhu mythos was the phrase "Cthulhu naflfhtagn." We already knew "Cthulhu fhtagn" meant "Cthulhu sleeps," and it wasn't too hard to guess what the prefix meant... If you don't get it, it means "not". So Cthulhu no longer sleeps.
The rats...can't you hear them!? It was the rats!
"glut! glut!" in A Tropical Horror, the sound made by the titular sea beast's razor sharp tongue striking flesh.
The Screwtape Letters: Screwtape writes to his nephew that in Heaven there is just silence and music, while in Hell there is the continuous noise.
In Michael Crichton's Jurassic Park, the T-Rex's roar, when first heard by the characters, is described as a horrifying, unbearable scream from another world. A character actually wets his pants while hearing it.
Gary Rydstrom, sound editor for The Movie, must have taken that description to heart, judging from the end result.
1984 has the disturbingly nonsensical song, "under the spreading chestnut tree, I sold you and you sold me. Here we lie, here lie we, under the spreading chestnut tree..."
It's even worse considering that in the end, the part about two people selling each other turns out not to be so nonsensical after all.
The "lobstrosities" in The Drawing of the Three. "Dad-a-chee? Dad-a-chock?" Of course, those adorable questions come right before they bite three of Roland's fingers off.
In the Discworld book Moving Pictures there is an instrument called a resograph ("thingness-writer"), which measures disturbances in the fabric of reality. It drops a small lead ball in the direction of the disturbance, which "...in severe cases may exceed —plib— two pellets —plib— during the course —plib— of —plib— one —plib— month". Or to put it in other words...
House of Leaves- The sound Navidson's house makes when it's layout changes
The moan of an approaching zombie in World War Z. Or the nonstop moaning of an entire swarm...
In the Ravirn novels by Kelly Mc Cullough, Eris' laugh is frequently described by Ravirn also known as Raven as sounding like glass breaking. Also, anytime the Furies or Cerberus' three heads speak in complete unison.
In John Dies at the End, the sound of Korrok's otherworldly worm minions is described as "...fifty thousand men trapped on a desert island, deprived of food and water and sex but somehow kept alive for fifty thousand years. Then, after they've been tormented a hundred steps beyond insanity, tortured past self-mutilation and cannibalism, somebody drops off a sculpture of a naked woman made of T-bone steaks. If you could then capture the sound of them simultaneously fucking and eating and tearing her to shreds and broadcast it to the center of your skull at ten thousand watts, it would still sound absolutely nothing like what I heard."
In Changes, Harry fights a vampire-summoned Mayan primeval monster, a complete Implacable Man called the Ik'k'kuo. Harry notes that its heartbeat is incredibly loud... and when you are in a completely dark building, an increasingly loud thump-thump is not what you want to hear.
