In Dylan Dog the storyline "Towards a Far Away World" (issue #140) references Slaughterhouse-Five with Vaal claiming to be an alien from Tralfamadore wishing to go back there, and an important location of the plot is an abandoned research base called Grilmiby Pill Industries Inc., which is an anagram of Billy Pilgrim.
One Adventure Time plotline involved Finn, Jake and the Ice King exploring a series of dungeons beneath his castle, eventually resulting in them each becoming trapped in an individual illusory world created by the Lich. The Ice King meets up with his fiancé Betty, who uses his crown to write the phrase, "everything is beautiful and nothing hurts" into a wall.
Footloose: When Wren and his mother go to a party in the small town they've moved to, one of the parents is complaining about the book and how deviant it is. When Wren pipes up he likes the book, he's immediately marked as an outsider.
Varsity Blues: Replacement quarterback Mox is reading the novel inside his teams' playbook.
Fobia: St. Dinfna Hotel has a copy of this book in the hotel's library, forming part of a Numerological Motif puzzle (other books having numbers in their titles, like One Flew Over The Cuckoo's Nest, Tale of Two Cities, The Three Musketeers, etc.) where you arrange the books to unlock an exit.
Life Is Strange 2 opens with the teenaged protagonist, Sean, having recently written a book report on Slaughterhouse Five, and been sufficiently enamoured with it that he's spelled out "So It Goes" on the lightbox in his bedroom. He and his father Esteban can have an optional conversation about the report just before the latter's death, somewhat appropriately, kicks off possibly the bleakest plot in the entire franchise.
Narbonic has an entire storyline where Dave Davenport Has Come Unstuck in Time. Dave does unambiguously do Mental Time Travel, but in keeping with the theme of fatalism repeatedly fails to change his past. Ultimately, he succeeds at altering history for the better only by accident - during of a fit of existential anxiety he turned down his first cigarette, and so never became a chain smoker.
Tiny Toon Adventures: The third and final segment of "Going Places" is titled "Slaughterhouse Jive". In this segment, the Tiny Toons visit the Montana Max Merry Meat Factory, where they are shown how meats are manufactured. After they avoid getting caught in the production line, they convince Monty to shut down his factory.
a toy Tralfamadorian out of a plunger, a glove, and a googly eye, and plays with it alongside her Barbies and Gundams.