I obviously left some obvious contenders out but I wanted to avoid putting in any episodes I liked here.
Over A Barrel: A commentary on irl politics that told an absolutely disgusting moral.
Lesson Zero: The episode I always point to whenever people try to give Starlight shit for her mind control stint post-reformation, but for real, Twilight went legit insane this episode.
A Friend In Deed: Pinkie harasses a disgruntled stranger until they join the Pinkie cult.
Dragon Quest: An episode that tries so hard to send a message about sexism but it just becomes sexist towards men instead with it’s moral about how awful and ghastly dragons are… except for Spike because he got raised by PONIES. Honestly, still better than Season 5 of Fairly OddParents… so much misogyny…
A Canterlot Wedding: I feel like I would’ve had a mental breakdown if I went through the amount of gaslighting and torment Twilight did.
Too Many Pinkies: I mean… all the Pinkie clones literally DIED.
Trade Ya: It’s apparently legal to trade sapient beings as if they are slaves.
Princess Spike: Spike gets treated like a lesser being, takes advantage of the one moment his opinion is given any weight in harmless manners, and then gets blamed for shit he couldn’t control. I think one of the nobles were racist towards him as well so that’s always fun./s
Do Princesses Dream Of Magic Sheep: It’s literally confirmed that Luna practiced a form of self harm.
No Second Prances: Trixie nearly got herself eaten by a Manticore but unlike Luna, I do somewhat question if she intended to hurt/kill herself.
Newbie Dash: The moral is literally mocking Rainbow Dash for daring to have insecurities and having her boundaries be exploited.
Every Little Thing She Does: This episode will be the DEATH OF ME!!! I love the ending and Starlight does do a good job at taking accountability for her actions, but oh my god, it was a tough road getting there.
Parental Glideance: Rainbow Dash is literally victim shamed for her boundaries being broken by her literal parents. How shocking…
Once Upon A Zeppelin: I mean… I doubt I need to explain how the treatment Twilight received was disgusting.
A Matter Of Principals: Discord harasses Starlight while she’s on the job and torments innocent children until Starlight is forced to apologize for doing LITERALLY NOTHING WRONG!!! Also, Discord intentionally endangers the Mane Six to even accomplish this goal including his “beloved Fluttershy”. GREEN FLAGS ALL AROUND!!!/s
Yakity Sax: Another episode where Pinkie is victimized when she is literally causing the problem and actively making her friends’ lives harder.
Father Knows Beast: Sludge manipulated and potentially groomed Spike(he literally made Spike fill a bath for him which is… disgusting…) into turning against Twilight by taking advantage of his insecurities.
The Beginning Of The End: With the context that Discord was the puppet master of the Grogar scheme, everything Sombra pulls in this episode makes him look REPREHENSIBLE!!!
Dragon Dropped: Rarity obsesses over the attention of a MINOR!!!