Parodied in Aqua Teen Hunger Force: MC Pee Pants, who's reincarnated to look like an old man, says that he tried to be sexy in his poster to attract vampires. Of course, the character wears only a diaper anyway.
One episode has Shake and Carl trying to score with a sexy construction worker named Dusty Gazongas. It's strongly implied that being sexy is mostly all she does.
Élisabeth "Sissi" Delmas is Ms. Fanservice in Code Lyoko. She's the one most often seen in some underwear, swimsuit or panty-shot scene. And yes, it's a kid show... but a French one.
Princess Teegra from Fire and Ice definitely belongs with her costume being a small thong bikini.
It's a natural since she was designed by Frank Frazetta... Frazetta specializes in fanservice.
The title character of Æon Flux runs around doing spywork and sabotage in outfits ranging from a skintight catsuit to a vinyl thong bikini and stripper boots. Aeon's appearance was originally conceived as a parody of unrealistically StripperifficAction Girls.
This trope is the one and only reason Cachorra was turned into an Expy of her own voice actress in Isidoro.
The producers seem to love the Male Gaze trope, especially with Courtney.
Dakota and Zoey serve in this role for the second generation cast.
Twin cheerleaders Amy and Samey serve in this role for the third generation cast.
Teen Titans: Raven and Starfire seem to be almost constantly tied for this position in the cartoon. In the comics, its a whole 'nother ballgame, as Starfire in the comics has what the original Terra described as a "balloon bod" that resembles a playboy model, and her outfit is best described as "bikini". They had to tone her down for prime-time children's viewing. Though one might wonder why the animators toned down Starfire below Raven, who was much less skanky and curvy than Starfire in the comics. In the toon, it's the other way round. Raven's outfit is at least comparable to the comic, but then again, putting a girl as young as the cartoon's Starfire in her Stripperiffic comic outfit would be almost criminal. For that reason, and for the fact that comic Starfire's personality is overwhelmingly uncaring of nudity and sex taboos, the writers decided to play up her comparative innocence. Given that the rest of the team include two veteran heroes, a half-demon and a recovering cripple, this makes more sense than in the comics where she was introduced, where Raven was the one who was comparatively innocent. This is subtly lampshaded in one episode where the two characters switch bodies.
The Legend of Zelda cartoon had... Fairy Companion Spryte. Only a few inches tall, she was as hot for Link as Link was for Zelda, once got an upskirt shot that revealed that she wasn't wearing underwear, took the chance to stare at him when he was naked in the bathtub, and one time even kissed him... when he was in frog form, to say nothing of making repeated passes at Link throughout the entire course of the series.
Justice League Unlimited has so many examples that exceptions (such as Amanda Waller and Killer Frost) are far easier to list.
In Ben 10, Gwen was a 10-year old girl and thus a Pettanko, and her teenage nemesis, Charmcaster, wore a coat that revealed no cleavage. In Alien Force and Ultimate Alien, however, the two are all grown up, with noticeably bigger breasts, Gwen having several scenes in swimsuits, and Charmcaster wearing a much form-fitting outfit. Although he may've just been mocking her, Ben said that she always had a big butt.
Futurama's Turanga Leela and Amy Wong both take turns at fanservice from time to time; but the verybusty Leela most qualifies for the title. Her standard outfit consists of skin-tight tanktop and pants, her other "ordinary" outfits (such as formal dresses and swimsuits) invariably have a midriff window showing her belly button, and she's the most likely to be seen wearing strange, Stripperiffic outfits. She's also the second-most-likely to get naked, after Professor Farnsworth.
Ty Lee from Avatar: The Last Airbender . And June, for the older crowd. This crowd includes Iroh. Too bad she was so underutilized... and as a result didn't meet up with Iroh again.
Suzie Chan on The Amazing Chan and the Chan Clan, like her brother Henry, is a subtle version. Her outfit is designed to show off her long legs and she looks quite fetching in a bikini, but the animators don't go out of their way to play up her sexiness at every turn.
Hilariously invoked in one episode of Megas XLR. While at a shopping mall, Jamie tries to get Kiva to wear a bunch of goofy and embarrassing outfits (including a punk-rocker chick outfit and pyjamas) as a petty joke on his part. However, Kiva just ends up provoking a different reaction from onlookers and the prank backfires.
The Baroness was probably the closest that G.I. Joe came to this (there's a reason she has a trope named after her) and some of her outfits were pretty risqué for a cartoon of the time. The most blatant example was one episode where she wore a bikini for the entire episode. (Not by her choice. Plot-wise, she, Cobra Commander, Flint, and Lady Jay were kidnapped by a third-party villain and forced into a Deadly Game, and in her case, she was in a spa at the time when she was grabbed, and had no way to change. Still, it was obviously an intentional move by the writers.)