Most of the female characters in comics by the Brothers Grinn tend to be top-heavy (and/or a bit on the chunky side) and lose their clothing very readily.Supermegatopia in particular plays with this trope. Several of the SMT characters have this as an actual Super Power, most notably the aptly named Distraction Damsel. A few of the male ones do as well, for that matter ("Buck Naked" and "Long Tom" of the All-Stripper Squad are exactly what their names imply).
Akila is the biggest example in The Noordegraaf Files. Her normal outfit is effectively a swimsuit, consisting of a strapless bra and a Dangerously Short Skirt. While she may seem innocent at first glance (such not having a nudity taboo, it's clear she knows damn well she's turning people on and she actively enjoys it. (Case in point: During a scene in which her and the protagonist are alone, she ends up sitting on his chest to read his mind. We then get this rather... suggestive exchange.
Theo: Do we have to do it like this? Akila: No, but I get a kick out of it.
The author said that he didn't originally notice the Subtext of Akila laying on top of Theo in a bedroom, but when he noticed how it looked, he just ran with it. Given how the Author loves to tease the readers, this is to be expected.
Haley the redheaded Action Girl has a few fanservice scenes, many of them ironic parodies of fanservice in general. "Gratuitous Bath Scene", "Wardrobe Malfunction", Show Some Leg, it's all there — but in stick figure format. The odd thing is, it still counts as effective fanservice, given that it's not hard to imagine what the characters would look like if drawn in a realistic style.
JuliaGreenhilt and Sabine are justified examples; Julia flaunts her attractive body in skimpy clothes to get her way ("Don't you want to look at the girl with the boobs? It always works on my teachers!") and maintain her status as most popular girl in school, while Sabine is a succubus so being a scantily-clad temptress is part of the job.
Most of the female characters in Ménage à 3 are attractive enough that their occasional nude scenes would qualify them for this title, and for that matter, most of the males provide similar services. Busty, blonde, French-accented, full-lipped, big-eyed, prone to wearing the skimpiest outfits possible and very generous with physical contact? That's DiDi, actually the most innocent of the cast (though Gary, also naïve in slightly different ways, could be a rare example of an Innocent Mr. Fanservice). The Shameless version is probably best represented by Senna and Matt (both of them lingerie models).
Missi from Misfile. As an author-acknowledged exhibitionist, she sometimes seems to be looking for an excuse to display the goods. Not that she has much to display, but then she makes good use of it. Not to worry too much though, the comic is strictly PG-13. Although it has to be said all of the female characters have served their time in the Fanservice stakes, especially Cassiel. Hell, when are the female characters not in some sort of over the top pose? Honestly it just gets silly at some point. The writer once had two characters get locked out of a house just so he could have one of them climb through a small window while wearing nothing but a bathing suit.
Monster Lands has Crimson Sally, who doesn't wear much and is quite flirtatious, as seen here.
GoGo from Van Heist appears to not take to the concept of modesty, throws it all around without really trying, but isn't interested in being sexy, really. And then you start reading the actual comic and see her personality is like that of a churlish orc woman. On ecstasy. Permanently. Bonkers does not even begin to describe many of her actions, made even more wacked-out seeming by her broken English and devilish anime-esque doubletakes.
In Chris Muir's Day by Day, both of the main female characters are routinely depicted in skimpy and/or body-hugging attire, and — with surprising (unsurprising?) frequency — in their undies.
Quite a few succubi qualify as this, particularly if you consider their emotional draws. The gold medal may well go to Nact'larn, however, who's the leader of the clan of lust. As one character succinctly expresses, it's a remarkable day when she's wearing clothes. (The comic's still PG-13, though.)
Cyndi of Penny and Aggie, particularly as drawn by Jason Waltrip. Big-bosomed, usually seen with plunging necklines and bare midriff, and quick to exploit the lust she provokes in students of both genders.
Brandi has arguably overtaken her in the fanservice department; not only has she been frequently depicted (implicitly) nude in bedroom scenes (which Cyndi only was once); she was also the subject of the comic's only pin-up filler to date. And then there's her ever-increasing bust size...
Saves-a-Fox from Goblins. Kin seems like she could be as well, now that the trauma of her existence has passed. Before that, it was definitely YMMV squickiness. There's also a "player character" who is all about this trope, from that three-person band that used to travel with Forgath and Minmax.
Yet Another Fantasy Gamer Comic... oh where oh where to even BEGIN? How about naming someone I know who isn't? Gren, the goblin. (And even there, you have her sister...) The pirate lady is also non-fanservice-y. That's about it.
In Seekers, Giselda's panties are often a topic of forum discussions and gag strips.
While the entire comic Oglaf is basically very funny fanservice, special mention goes to Evil Overlord Mistress.
Pirta and Sandy often fill this role in The Whiteboard, most notably in previous April Fools' Day strips that played up the Fanservice. As well as the occasional strip that plays it straight, such as when Sandy dresses as Krystal for her boyfriend Swampy.
Velvet Hairyson of Deer Me is such a Dude Magnet that just about every secondary male character she comes across is immediately entranced with her. This is lampshaded in one strip where Viana brings Velvet along to the public pool. Everyone becomes so entranced by Velvet's presence that Viana gets the pool to herself.
In just about every one of her appearances that Amanda of El Goonish Shive ends up transforming, she usually ends up shrinking or turning into a Half-Human Hybrid. This is Fanservice for a particular segment of EGS's fanbase.
Homestuck: Snowman/The Black Queen and Her Imperious Condescension have each been drawn in fanservicey ways at least once, but in her short time so far as a character, Porrim Maryam has outmatched them both.
Brooke McEldowney's webcomic 9 Chickweed Lane had, and continues to have, a strong fanservice element to it in its depictions of female characters, most notably Edda. The later spin-off Pibgorn appears to be some 80% fanservice: The starting point of this strip is a menage à trois between an unassuming bespectacled pianist and musical arranger, and two devastatingly gorgeous supernatural entities who are devoted to him; namely, a dark succubus called Drusilla and a red-haired faerie called Pibgorn. Neither entity wears very much at the best of times and the casual reader might suspect the script is written to get them naked as often as possible.
Grrl Power is fairly open about the fact that most of the characters, male and female, are going to provide some fanservice at some point, and this is lampshaded in The Rant, and occasionally in the strip.
In Frivolesque, the well-endowed Liliane Bougainville stands out among the rest of the female cast. Even her icon is cleavage.
In Cassiopeia Quinn, "pantlessness" is listed as one of the title character's likes.