Pete is clearly a psychologically Abusive Parent in the Goof Troop canon, but in the fanfic Anything Or Nothing, the author extends it to physical abuse. The lack of Social Services is explained by PJ (and his mother Peg) being too afraid of Pete to alert anybody to the problems. Consensus among reviewers is that it's frighteningly realistic in the portrayal of the abuse and how it is covered up by the family from friends and authority figures.
Shows up a lot in Brainbent. More prominent examples include Rose's mom (emotional/psychological) and Dave's older brother (extremely neglectful; emotionally and possibly sexually abusive)).
There's quite a few Harry Potter fics out there that take the Dursleys' abusiveness and ramp it up to eleven. One particularly painful example is Whelp, which begins with Vernon punishing a seven year old Harry with no food [after he had previously spent two nights without food] for not cleaning the patio, even though he did clean it before Dudley tracked mud all over it. Then, when Harry tries sneaking out of his cupboard while everyone's asleep and eating from the garbage, Vernon catches him in the act and punches him in the face numerous times before locking him outside. Petunia wakes him up by spraying him with the hose, and when Vernon comes home he chains Harry up like a dog in the backyard, and gives him nothing but water and dog food for dinner. Needless to say, it is IMMENSELY satisfying when Snape comes into the picture...
Hivefled, 'nuff said. Further elaboration; the Grand Highblood and the Condesce went out of their way to have offspring and track them down, against the social norms of their society, specifically so they could do terrible things to them.
One example is in The Nuptialverse, where they are emotionally abusive, constantly treating her like a foal and putting her down. When she stands up to her father, he starts beating her.
In the same series, Pinkie Pie's father became emotionally distant after his mother died, culminating in hitting Pinkie and accusing her of wasting his time when she got a cutie mark he didn't approve of (her mother didn't partake, but didn't stop him). This led to Pinkie running away and ending up in Ponyville. Unlike most examples, however, they're revealed to have eventually regretted what they'd done and try to make amends.
Helping Hoof's father forced him to act exactly the way he thought he should act, never letting him do what he wanted. As a result, he never got his cutie mark. Because of this, he called him worthless and belittled him, driving him to work for Checker.
Queen of All Oni: It seems that when Drago was sealed away by Lo Pei, Shendu intentionally left him that way in order to "build character".
Jade's parents almost veer into this from Parental Neglect; Tarakudo uncovers in a dream that after injuring herself exploring (sliding down a banister), her mother's reaction was to spank her for disturbing the adults' party rather than concern for Jade's well being (she ran into a statue at the end of the railing and had severe bruising and was crying). Jade truly considers going to live with Jackie to be the best thing that ever happened to her before she went evil.
The notorious Shinra High SOLDIER has three prominent examples: Julia's mother and father forced her into prostitution when she was younger and locked her up in a mental institution for three years. Her father beat and raped her, and ultimately tried to kill her. Hojo has been physically and mentally abusing Sephiroth since he was born.
Javier's parents arent much better, they kicked him out of home when he was in his teens, forcing him to have to deal drugs and even prostitute himself while living on the streets to get by.
Mei Shirakawa's parents in the Horseshoes and Hand Grenades sidestory Wheel of Fortune don't care about the problems their daughter has to go through regarding Yamada Tatsumori's tyranny over her High School, with the mom going as far as to leave Mei in the hospital despite going there to check on one of her friends. It's later revealed that she was supposed to be the next heir to a family fortune by showcasing her untapped psychic powers which are attuned to her stress levels. The parents emotionally abuse her to get the powers to spike. They get killed off by Renenutet.
Mary Jane Watson grew up in a broken home, as she and her mother suffered appalling physical and emotional abuse at the hands of her father. This left Mary Jane with some major anger issues, and she originally becomes a superheroine for no better reason than to spite her superhero-hating father. A major part of her Character Development involves Mary Jane coming to terms with her childhood and fighting crime for the right reasons.
Little Bruce Banner was molested by his psychotic mother Rebecca Banner, who also viciously intimidated Bruce's father Brian to keep him from protecting their son. The anger Bruce felt at what was done to him, and his hatred of his father's pathetic weakness, were both major factors in his being so unstable when he became the Hulk.
Spider-Woman's enemy Polestar was repeatedly humiliated and ridiculed by his parents for not being as athletic as his older brother or as academically gifted as his younger sister. When he gained superhuman powers, one of the reasons he became a supervillain was specifically to humiliate his family by being associated with him.
The Green Goblin became an obsessive control freak who enjoyed terrorizing the people around him after he saw the way his father had destroyed the family fortune through his drunken binges and lack of self-control.
It's heavily implied that the reason that the Brothers Grimm became such Psychopathic Manchildren was because of all the cocaine their mother did while she was pregnant with them.
In the Fairly Oddparents fanfiction, Never Had A Friend Like Me, Amanda's parents are never going to win a parenting award. They never wanted kids and don't want to waste time, energy, or money on the one they ended up with. They aren't physically abusive towards her. Emotionally and mentally, however... Well, when even Norm feels bad for you, you know that the kid deserves a break.