This is based on opinion. Please don't list it on a work's trope example list.
Nightmare Fuel / Known Space
Several of Larry Niven's Known Space series involves organ banks, where criminals are taken apart and put in storage to be used as transplants. As a result, since everyone wants to live forever, more and more trivial things end up being voted the death penalty, like speeding. For people who want things like a young heart, instead of a good-enough-but-older one, or a new liver after destroying yours through drinking, people go to organleggers, criminals that kidnap people and hack them up to order.
And if that wasn't bad enough, in comes Body Horror: in one story, two kids with rich parents are kidnapped for ransom. One of them is returned insane, as they hooked her brain into an induction device and stimulated her pleasure center long enough to make her all-but catatonic; the other one is just acting a little oddly forgetful, missing some skills. It turns out that the diseased and dying organlegger had hulled out the boy like a melon and replaced his brain and spinal cord with his own.
In "The Patchwork Girl", a woman described as "the most beautiful woman alive" is convicted of attempted murder and cryogenically suspended for six months, after which she'll be broken up for organs if no new evidence comes to light. Except for that other lady who just got injured, needs some new parts and happens to be a match for Naomi. Only, oops, it turns out she was innocent after all, so they put Naomi back together with replacements that don't quite fit. She's described as looking "blurred" later, instead of as attractive as she once was - the titular "patchwork girl".
The Bandersnatchi existed for two billion years with nobody to talk to but each other and - with no hands or other manipulative organs - nothing to do but eat food yeast. One character is horrified at how lonely they must have been.
After losing a string of wars to the jumped-up monkeys from Earth, a Kzin warrior decides Man is the Fanged God's favored species after all, and starts a cult that eventually becomes the Kdaptist religion, whose rites include staging the Crucifixion with a living victim as Jesus and skinning humans to make people-masks out of, in the hopes of tricking the God into mistaking the Kzinti for humans.