Lucy is always throwing her weight around and slugging the other kids (not just Charlie Brown - probably her most frequent target is her own little brother Linus). The other kids never really call Lucy out on this or try to stand up to her, and she rarely gets in trouble. Charles Schulz also went on record in several interviews as saying that while a boy bullying a girl wouldn't be seen as funny, the gender reversal in a girl bullying a boy would be seen as funny.
Lucy is the most obvious case but all of the girls have some level of violent streak. Even Marcie is surprisingly eager to slug people in some strips. Linus' blanket whip is as far as it goes for the boys and that only gets used against people off-screen.
One running gag in Snoopy's stories was to have a man say a bad pun or something stupid. The woman would then hit him with any manner of objects.
In Bringing Up Father, the title character, Jiggs, would often have various kitchenware thrown at him by his wife. An early MAD parody from The '50s deconstructed this by having an Art Shift on every other page where Jiggs is suddenly drawn realistically, and is covered in blood and scars, and has missing teeth due to his wife's beatings.
Played for laughs in one strip ofLuann, where apparently the classic sawing-a-girl-in-half trick is seen as violence against women. When Bernice suggests sawing Gunther in half, the counselor doesn't see a problem with it.
In Calvin and Hobbes, while Calvin is obnoxious and belligerent toward Suzie, whenever it comes to violence more serious than the odd snowball, she always gets the upper hand.
FoxTrot: Paige often gets away with beating up her little brother Jason. There are times where she gets punished for it, but it's still hard to imagine a 14-year-old boy beating up a 10-year-old girl being Played for Laughs in the same way.
In a 2006 strip of◊ Garfield, Jon attempts to hit on a woman. The woman, apparently unprompted, responds with a long spiel - half the panel - detailing the (cartoonish) physical abuse she's about to inflict on him. Either Jon is just that repulsive to anyone not named Liz, or it's this trope in action.