Alpha Flight: Puck. Shorter than Wolverine, hits just as hard. Even in a prequel story before he lost his height completely, fulfilled this trope.
Ant-Man: Anyone who uses Pym Particles (most notably, Ant-Man and The Wasp) can shrink down to the size of an insect while maintaining the strength of a normal-sized person.
Asterix is drawn as smaller than most characters (and sometimes referred to as "the small one"), but turns into this when drinking the Magic Potion.
Al Pratt, the original Atom, was only 5'1". That's where his nickname originally came from — he was small. But he took up boxing and later actually gained super strength.
This is literally a tactic employed by Ray Palmer. He shrinks down to a tiny size, but his mass doesn't changenote Or, rather, he has just as much control over his mass as he does over his size, so it's basically whatever he wants it to be, which means he can pack a wallop... or tear through somebody like a freakin' bullet.
A defining trait of all of the Robins, especially Jason Todd and Damian Wayne, though poor Tim Drake gets stuck remaining as one as a young adult after he was introduced back when he was thirteen.
Cassandra Cain, the second Batgirl, is this even as a young adult, being 5'5" or shorter but physically stronger than almost any other member of the Bat-Family.
Of Batman's Rogues Gallery, Penguin can sometimes fall into this category, though usually not against Batman. Against big guys who are goons or minor characters, Penguin can get the chance to show what he's made of more, being able to knock out larger men with a single punch or break their noses with a single umbrella swing.
Benoit Brisefer: The titular protagonist is a little boy with strength that can match that of Superman.
Black Canary: Not usually emphasised too much, but Dinah Lance's official height is given by official profiles as 5'4" inches, and she's usually drawn significantly shorter than the people she fights (and quite often who she fights alongside). This actually works to her advantage as, besides the fact it means she's frequently underestimated, but it meant she was at a significant size disadvantage when being trained by Wildcat, so from the beginning she was trained to punch above her weight and make use of her small stature.
The Boys: The Female is a teenage Japanese girl who is (maybe) five feet tall and a hundred pounds soaking wet, she is the biggest physical threat in a whole team of them (well, apart from Hughie). Frenchie even says that were it a straight-up fight between her and Butcher, it would be over very quickly, and in her favor.
Captain America: Steve Rogers was once Brought Down to Normal, something that for him meant returning to be a scrawny and sickly-looking guy. He could still unleash a No-Holds-Barred Beatdown on three thugs injected with the Super-Soldier serum, thanks to months of training, years of combat experience and the thugs letting him grab a fire extinguisher.
Cerebus the Aardvark: Cerebus is three feet tall, one of the physically strongest and most skilled fighters in the world, and has repeatedly taken down squads of veteran soldiers by himself.
Cindy and Biscuit: Cindy is a pre-pubescent girl who regularly beats monsters several times her size to death with pieces of wood. Her Establishing Character Moment in the very first story has her hitting an alien over the head with a stick hard enough to smash its spacesuit helmet to pieces and utterly pulverise its head.
One soldier holds off at least half a dozen Mundy rats and gets back to make his report on Bluebeard.
In "March of the Wooden Soldiers", at least half a dozen, mounts and riders, die as the soldiers pry out the pegs connecting the knee joints of the titular soldiers.
Garfield: In one strip, Garfield climbs up a tree where a bird is singing, saying, "Ready or not, here I come!" Then there are sounds of a ferocious fight, and Garfield is thrown out of the tree, beaten to a pulp. "He was ready..." groans Garfield.
Knights of the Old Republic: In Issue #38, Zayne's crew comes across a member of the diminutive Bimm species. Said Bimm turns out to be both a serial killer and a Sith, and quickly defeats Zayne in a lightsaber duel despite being less than half Zayne’s size.
The Life and Times of Scrooge McDuck: Young Scrooge is only half the size of most other (dog-nosed) characters, but he fights like a force of nature. And for that matter, also Old Scrooge, his nephew Donald and some other members of their family show tendencies in that direction.
Li'l Abner: Abner's mother Mammy Yokum. She's one of the shortest characters but incredibly strong, capable of beating up several men taller than her, lifting entire houses off the ground, and carrying a team of cattle.
Peanuts: Here's an extreme example. "World War II" (a.k.a. the cat that lives next door) is a vicious creature that Snoopy is afraid of (and yet someone that he always insults) who often rips his doghouse to pieces. The rare times they've fought have always ended badly for Snoopy... And yet, somehow, Woodstock won a fight with this cat! After it had beaten up both Snoopy and Linus, no less! How Woodstock did this is a mystery.
Popeye is noticeably shorter than most of the characters in his strip. It's not uncommon for his adversaries (especially Bluto) to call him a "runt". That being said, he also exhibits super strength is not one to turn away from a fight. And if he decides to pull out a can of spinach... run!
The Powerpuff Girls: In "Creature at Large!" (DC issue #9), when the Powerpuff Girls finally catch up to the Monster of the Week, they find that the monster is smaller than they are (and they qualify as pint-sized powerhouses themselves), and yet the monster thrashes all of them effortlessly. It still loses to an 18-wheeler, though.
PS238: Micro-Might's power is to shrink herself, becoming denser and stronger the smaller she gets.
Richard Dragon, who eventually became the best unarmed Badass Normal male fighter in the DCU, was shown as doing a decent job fighting three bullies who were older and bigger than him when he was a tyke before ever starting any training. They still beat him up but it took pulling a Kneel, Push, Trip trick before they could even properly land a blow on him, and then he started actually learning how to fight.
Runaways: Molly Hayes is a superstrong mutant and a preteen girl. Marvel's website actually named her the fourth toughest female on their roster, following She-Hulk, Ms. Marvel, and Rogue.
Spider-Man: Peter Parker, while average by real life standards (5'10"), is practically dwarfed in size when compared to the vast majority of his allies and enemies, Wolverine being the notable and perhaps only exception. Spider-Man has the proportionate strength of a spider, and can lift hundred's of times his own body weight. He has been known to lift and use CARS as bludgeoning tools without effort.
In Ultimate Spider-Man Peter Parker stands at around a petite 5'5, making most people he comes into contact with tower over him. However, he is shown to lift cars and trucks with hardly any effort.
Jimmy Olsen during the earlier stories of his series. A teenager who is capable of beating a taller, beefier crook in a fight. One comic has him getting into a fight with a crook posing as Superman. The bad guy never lands a hit on Jimmy, who pummels him sufficiently to keep him from getting away.
The Transformers (Marvel): Buzzsaw. From the show you know him as "the bird-thing we rarely see who looks like Laserbeak but in orange instead of red.'' But in the comics, he makes a habit of utterly handing full-sized Autobots (and more-than-full-size Autobots, such as OMEGA SUPREME) their skidplates. Worse, he's psychotic even by Decepticon standards: he considers himself an artist and the precise mauling of his enemies the ultimate in beauty. If you ran into him, you'd laugh at the Minicon-sized bird that's acting like he's going to fight you or something... for about two seconds. Then you'd find yourself being agonizingly turned into a gutted "masterpiece."
The Transformers: More than Meets the Eye: Tailgate is a tiny, good-natured Transformer, who — after gaining Outlier powers from a traumatic experience — becomes a powerhouse. At one point, most of the ship is in trouble because of Sunder, whose eyes can make a Cybertronian turn inside-out. After Rung blinds Sunder, Tailgate picks up the Rodpod — a Cybertronian shuttle that has enough room for twenty-odd full-grown Transformers — and crushes Sunder into scrap metal with it.
Watchmen: Rorschach is an unassuming man who stands 5'4, yet frequently kicks bar-fulls of ass. Interestingly, he wears thick-soled shoes to make himself look taller.
Wonder WomanVol 1: Diana and Steve Trevor's daughter may not have her mother's longevity, but she does have her strength. When she's all of five her favorite toy is a large solid iron ball that could be mistaken for a beach ball for the way she tosses it around.
Wolverine is 5'3", and one of the two or three most dangerous non-super-strong characters in the Marvel Universe in close combat. (He even beat the Hulk — check that, he almost killed the Hulk — once.) Wolverine's Healing Factor does give him limited super strength as well, particularly combined with his adamantium skeleton, allowing him to take fuller advantage of his muscles' capabilities.
His Opposite-Sex Clone/daughter X-23 is generally depicted as being even smaller, (both shorter and far more lightly built, being officially 5'1" and a rather slim, if athletic, teenage girl) and may be an even more dangerous fighter. Although Laura's skeleton isn't bonded with adamantium, as with Logan her Healing Factor pushes her strength somewhere beyond the human peak for a woman of her size. It's really saying something that in Marvel: Avengers Alliance she's considered a Bruiser. This puts her in the same class as Hercules, Hulk and Thor.
Rogue, while she’s taller than Wolverine and Jubilee, still stands at 5'8 while her husband Gambit is noticeably quite bigger than her at 6'2. However she can kickThe Juggernaut’s ass while he definitely can’t.
Sunspot, when he was a New Mutant, was a measly 5'4" and one of the shortest members of the team. He was also their biggest bruiser, since his mutant power was a form of Super-Strength.
Jubilee, a petite teenaged girl who, on the New Warriors, used power gauntlets to become the most physically powerful member of the team. With her old powers, she was still quite the powerhouse. Basically, when she's really pissed she can take what started as a mostly harmless lights show up to eleven, resulting in massive kaboom. (Basically, she becomes her video game/animation self.) And these days, she's a vampire.
One of the Guardians of the M'Kraan Crystal in Marvel is known as Jahf, who is a dwarf only 3 feet tall, yet capable of throwing down and beating the likes of Gladiator. Inverted with the next guardian, Modt, who is the size of a giant and has all the physical power you'd expect.
Forgotten Realms: One issue has the halfling bouncer of Lady Rae's tavern. She wears a magical girdle of storm giant's strength, allowing her to pick up Vartan Hai Sylvar—an elf more than twice her size and clad in plate armor—and hoist him over her head without effort.
