In season 1's "Exes and Ooohs", we meet Moxxie's father, Crimson--throughout the episode he is physically and mentally abusive to Moxxie, and flashbacks prove he's been the same way since Moxxie was small.
In the season 2 premiere, "The Circus," Stolas' father Paimon forces him into an arranged marriage with the shrewish Stella and is implied to be supremely neglectful. We also meet Blitzø's father Cash Buckzo, who not only sells Blitzø to Paimon for literal pocket change but then goes on to demand the child steal as much as he can carry out of the house.
One repeated character is yelled at by his wife, and has items thrown at him and smashed on the walls, in response to him cheating on her.
A one-off character murders her spouse for cheating.
Moxxie's father was implied to be severely abusive to his wife in the past--contrarily, Moxxie dotes on his wife Millie, and the relationship is amazingly respectful and healthy.
In a scene where the characters are observing nature, some bunnies are torn apart by wolves, a wolf is attacked by a bear and the bear gets crushed by a falling tree.
It's not onscreen long, but in "The Circus", Paimon shows Stolas a photo of young Stella. She's violently strangling a small dog-looking creature while a second one looks on tearfully.
Blitzo gives Loona a present that explodes into a bunch of spiders with the comment of "you love spiders". Loona is less than impressed. Spiders crawl all over her and one bounces from a thread off her nose.
Some characters have features of snakes, the most visible is "Striker" in episode 5. He got a tail that rattles like a snake, and his movement are very "snake-like"
Moxxie gets bitten by a shark a few times, and in S2: E3, there seems to be a species of shark-like demons which appear prominently throughout the episode.
In episode 1, while it isn't explicitly shown, the family the characters attack has a cooked dead person on a serving plate. They also show a brief scene of eyes and other gore being in a salad.
In S1: E5, Striker tries to choke Moxxie to death. He almost succeeds, but is interrupted. He tries to do it again in S2: E4, but fails again, and the act itself is far less intense than in the previous attempt.
I believe there is multiple times a bone is broken, but the one most noticeable is episode 5 s1, during a fight a character break their arms with an open fracture
In Murder Family, both the father and mother characters are killed; the mother being shot in the head while the father is killed within the exploding house.
S1:E2 | A character vomits into a bucket at the 8:00 mark. No vomit is shown, but retching can be heard.
S1:E3 | A background character vomits on screen at around the 8:50 mark. This is in a cartoon-ish manner, but is complete with audio and the subsequent shots show said character in a pool of his vomit.
S1:E4 | A character vomits at the 6:27 mark. Her cheeks puff out as she retches, but the camera cuts away as she actually vomits. There are graphic sound effects and the puddle of vomit can be seen on the floor in the subsequent shot.
As of S2E3, no bi/pan character has cheated on anyone. In S2E3, another character tries to seduce Moxxie, a bi character who is married, but Moxxie rejects him.
The O Blitzø's name is silent (I'm guessing he changed it because he doesn't want to be associated with the circus he grew up in), but people constantly disregard this, usually on purpose just to upset him. I'm not sure if this counts as deadnaming, but I'll put it here just to be safe.
No but in episode 1, the teacher shoots herself in front of her children.
In episode 4, the old man tries to kill himself but fails, he is accidentally killed by the cherubs at the end though.
Blitzo says Loona cannot come to the human world because of the "freaks up there who'd drool all over [her]". Blitzo, Loona, Moxxie and Millie proceed to glare disapprovingly at the camera for a moment.
It depends on whether you consider it a joke or not, Blitzo and Moxxie wear a dress in the episode for a brief amount of time but it isn't really the butt of the joke
In episode 3 (I think), IMP kills a bunch of humans. The humans are seen behaving in a sexual/romantic manner with others, including straight, gay and polyamorous relationships. Some humans are also shown with top surgery scars. None of them are specifically targeted due to this, though.
In the pilot, when Moxxie asks Loona why he's being faxed a weight loss ad, she only responds with "C'mon, you know why."
She also calls Moxxie a "fatso" in episode 4.
There is so much sexual content. Every episode has some form of sexual joke, punchline or scene. If this is a sensitive topic for you, it is best you avoid this show altogether.
In s2 e3 a character drowns on screen, it’s part of a larger flashback scene involving several other deaths and a lot of abuse/manipulation. It was triggering to me and it’s not even something I’m generally triggered by starts at around 13:20 at about 13:57 (the drowning part, the flashback starts at 12:30ish)
The scene is not super important, and mostly is just to demonstrate that moxies dad is abusive