* Heart Girl from the ''GlobalGuardiansPBEMUniverse''. Imagine Superman as a nine-year-old blonde girl with pigtails.
** Nicholas Chandler also. A fourteen year old boy who is perhaps the only "monster slayer" on the planet more feared than Charles Carr. At age eight he used a baseball bat to kill a menacing spirit he still thinks of (at the grand old age of eleven) as "the Boogeyman". Considered the "creepy little kid" in his neighborhood, and is distrusted by parents and children alike... until the children come to him telling stories of strange things bumping around their windows at night. Lives with his parents, naturally.
* There are plenty of CuteBruiser characters at SuperHeroSchool [[WhateleyUniverse Whateley Academy]], since these are future superheroes (and supervillains and superpowered people trying not to be either). Of the main characters, Tennyo and Phase fit this trope. But the best match is probably Desidera, codenamed 'Diz Aster', an 11-year-old girl who's at Whateley because there's no other place safe to hold her. She is a PK supergirl who can apply 8 tons of force at a mere touch. And ''[[CursedWithAwesome she can't turn it off.]]'' She does everything with 8 tons of force. Typing. Opening the door. Changing clothes. She can't leave her room without putting on a special power armor suit whose sole purpose is to 'use up' her PK force and keep her from destroying everything she touches.
* Dark Rose of Blood, the leader of ''LessThanThreeComics''[='=] Teen Dream Team, is a cute teen gothic lolita who packs one hell of a punch. A particularly egregious example of her fitting this trope is her second fight against Tarantula.
* Though several characters of this type exist in ''FateNuovoGuerra'', the clearest cut one would Kosviel von Einzbern, a Justica model homunoculus who cosplays as her favorite visual novel character regularly... and can kill you like that character does.
* ''ShadowUnit''[='=]s Nikki Lau may well qualify as this.
* Saga of ''Literature/NottingCove''. Characters comment on her cuteness and she easily defeats a character known for being ridiculously strong. She's also the youngest of the cast.