What's worse than being mind raped? Being mind raped by a Giant Spider. One who is quite clearly enjoying herself. N'Ktane does this in Tasakeru.
And so does her "son", Stalker, later in the same series. And he doesn't just stop at mind rape...
In the second I'm a Marvel... And I'm a DC story "Happy Hour", The Joker's plan essentially involves using a mind-controlling cyborg to rewrite the memories of all the superheroes to make them Darker and Edgier by putting them under the delusion that everyone they ever loved had been brutally murdered right in front of their eyes. He also uses that android to psychically torment Green Goblin by forcing him to learn the entire Portuguese language... all at once.
Given that Mortasheen is a horror take on the standard Mons setting, you could probably guess that this trope pops up a lot. It is most notable in the Devilbirds, most of the Vampires (Who have some level of hypnosis to lure their prey to them) and about half the creatures in the Unknown category.
The Slender Man sometimes does this to people, perhaps when he feels they're resisting him too much, perhaps just as a side effect of his presence.
Happens in Arcana Magi to Alysia Morales and Reya Everheart. The process is called Therapy and for Alysia, she found it humiliating before her mind broke and she was no more, but for Reya, she is completely afraid of it and even warns Alysia not to mess up or else.
What happened to Cavalier and Skybolt in the Whateley Universe. And it turns out to be worse than we suspected.
Red vs. Blue Revelation has Tex state that part of Alpha's torture was being placed in scenarios where he was forced to try and fail to save his loved ones, and being forced to watch them die. Repeatedly.
Further, it was tortured this way by facets of its own personality (Gamma and Omega) on the order of the human it was based on. Which would add that it would believe itself capable of inflicting this sort of agony on others.
In season 10, it's implied that the third Tex underwent a similar process as the Alpha; when Epsilon finds her, she's as broken as the Alpha was just after his Mind Rape.
Brave New World Universehas this happen several times in Tech Adventures. First is Maria the resident psychic who enters enters the Jokers (Not the DC Joker) to take over his body and send him to the police. He proceeds to torture her for what seems to be years driving her insane. Then Sasha, who has already been broken, and is almost catatonic is visited by a psychic big bad, Mindwurm, who proceeds to make him relive every bad moment in his life, and then uses the demons in Sasha's mind to destroy the last embers of hope. When this doesn't work out so well, Mindwurm goes back into his brain and effectively lobotomizes Sasha by destroying his memories one by one. In the final fight, Maria takes whats she's learned from the Joker and Mindwurm, and tries to do this to Joanna the final big bad with some success.
This is basically how the story of Broken Saints treats Shandala. She suffers one horrible thing after another in her life, eventually resulting in becoming an empathic weapon designed to do this to millions of people across the world, employed by the Big Bad in his plan to all but restart human civilization.
Again Tech Adventures from Brave New World Universe has Sasha getting mind raped through a chemical cocktail which drives him temporally insane, when a mercenary group tries to capture him. It doesn't end well for the mercenaries as it causes him to go into a rage.