Subverted by El Goonish Shive; Diane fits the stereotype perfectly, but the setup turns it inside out. First, we see her as a "Mooching Tease Pimp" and Nanase keeps brushing off her attempts to get her into the Girl Posse. Then, Diane does one Sherlock Scan and is shown to be caring, implying that it's just an act. She seemed to be the most shallow and mundane character around, but now we can only guess who and what she is. It is almost certain is that she's not a magic-user.
Subverted by Footloose; Sparkle is very intelligent and somewhat Genre Savvy. She still gets her comeuppance though.
Subversion: In Penny and Aggie, Penny is a popular girl, and seems like a textbook example at first (in contrast to the independent-minded Aggie). As the story progresses, however, Penny turns out to be a decent, observant, intelligent person, with most of the conflicts between her and Aggie being initiated by the latter.
On the other hand, Carrie of Loserz is the epitome of this trope, or is at least trying to be. See here.
Sayuri Morita in Red String. However, her nastiness eventually comes back to bite her, and the main characters actually haven't gone and befriended her yet.
Felicia Laine in Ozy and Millie fits most of the characteristics of an Alpha Bitch, despite being in elementary school. In subversion of the trope, however, she's not stupid (as much as she acts the part), nor does she have any attraction to the strip's Jerk Jock Jeremy (indeed, they've never even met). Her infatuations are mostly directed at the members of boy band du jour.
You'd think that with cheerleaders as protagonists, Cheer! would be free of Libbies. You'd be wrong.
In Blip, Mary is a narcissistic, shallow, vain robot. On at least two occasions, she's been accused of using her Alpha Bitchiness to mask insecurity. Notwithstanding, she does seem to care about K and her friends. Maybe. At the start of the comic, she and K had a nasty falling-out, and refused to speak to each other for years. Mary makes the first reconciliatory gesture, and the two proceed to immediately bury the hatchet.
Though a minor character, Julia Greenhilt is clearly the Alpha Bitch of her magic school in The Order of the Stick, complete with two tagalong friends with whom she gossips about other students' clothing choices.
Vanessa has all the hallmarks of this in Disney High School, complete with her own Girl Posse (Cinderella's stepsisters) and a habit of sneering down at others she perceives as inferior. Her main role in the story line is trying to sabotage Ariel and Eric's relationship so that she can get him for herself.
Eerie Cuties: Melissa Hellrune provides the trope image. Though she and her Coven were pretty high on Charybdis Heights' social ladder and were admired for their looks, she was stuck being second fiddle to Layla, who was more popular than she was. Naturally, Mel wasn't going to stand for it and plotted to overthrow Layla, along with trying to steal her boyfriend.
In Giant Days, where Esther de Groot from Scary Go Round goes to university, she meets three former head girls, each of whom was probably the Alpha Bitch back at their respective schools. Although instead of (or perhaps "in addition to") cheerleading, each of them knows a specific style of martial arts.
Bridges features head cheerleader Lana, who is controlling of her squad to a borderline psychopathic level.
Lulu Cthulhu features three of these who have undertaken the mission to make all the losers feel accepted at Valentines' by giving chocolate to losers. They genuinely don't seem to understand why being singled out as losers doesn't make people happy.
Princess Pi has Sam, Alex, and Butch, also known as the Totally Nazis. The story "Princess Pi vs. The Alpha Bitch" even uses this trope's name in reference to Sam, although Pi expresses confusion about the term's meaning.note She thought it referred to a canine Sesame Street character who helped children learn about letters.
Zodiac Blues gives us Lia, who calls even her boyfriend a 'loser'.
Drowtales demonstrates this at least in the early chapters in the form of Chrys'tel Vel'Sharen and her Five-Man Band. Though it should be said that she has turned traitor to her clan, and the rest of the 5 man band has either joined an enemy faction, died, rebelled or is just plain abandoned.
Dreamkeepers Prelude gives us Stacephanie and her Girl Posse Triffany, Ashleybelle, and Leslieanna. They focus on belittling Lilith, but will turn on each other if necessary.
Vampire Cheerleaders: Lorna Thurston is the captain on of the Bakerstown High cheerleading squad and the "queen bee" of a Coven of vampires. As such, she's pretty much what you'd expect, though her Coven thinks of her as being the lovable variety.
Sequential Art: Hillary Locke, Kat's rival since grade school, is this sans the posse. She torments Kat at every opportunity because of a competition for popularity that seems to only be happening inside Hillary's own head. Hillary is also not above using sex to manipulate others, and thrives on any positive attention she receives. From Kat's viewpoint, Hillary is a sadistic slut who just randomly decided to start bullying her and refuses to stop.
Pre-teen version in the NarbonicSpin-Off Babies strip Li'l Mell, where Mell's first grade class has two Alpha Bitches; best friends who are both called Taylor.
Lifeofan Aspie gives us Hoshiko, Ayame who fits the mold (reasonably attractive, associates with the "popular" guy, has a posse, hates the main protagonist for petty reasons) quite nicely. However, her reason for not liking the autistic main lead what with Susan looking at her funny (albeit not intentionally so) combined with the latter physically assaulting the popular guy for something that wasn't even his fault gives her a bit more depth than the standard stereotype. Nonetheless, Ayame's holier than thou attitude gets her a stern verbal beatdown by Susan and eventually a physical one by the same person as well.
Apricot Cookie(s)!: Jammy Smasher takes the leading role in mocking Apricot for her inability to transform.
Rascals: Ever since the introduction of Amanda, she has shown rage and anger towards Chrissy.
Tiffany from Big Jo is mostly this, though she has a bit more depth.