In the direct-to-DVD movie Pollyworld, a girl named Beth is one of these. She even goes so far as to help Polly's almost future stepmother try to get rid of her by sending her to boarding school.
Beth has been tormenting Polly in other stories as well. In the very first one, Beth tried to prevent Polly's all-girls band from playing at a school event. In the second one, she tried to prevent Polly from making a speech. Fortunately, Polly's look-alike cousin Pia could deliver the speech for her.
Mertle from Lilo & Stitch (and its subsequent TV series), all because Lilo is 'too weird' for her. That, and she's spoiled rotten by her mother. It's implied that she gets her nasty side from her aunt, and has an inferiority complex. In an interesting variation, she looks more like a stereotypical nerd than Lilo.
Regina in the first movie. Her Meaningful Name is Latin for "queen", and, despite being feared by every person in the school, every single one of them wants to be like her or be liked by her. The movie is a deliberate embodiment and analysis of this trope. The protagonist eventually becomes the new Alpha Bitch in true Macbethian fashion after Regina becomes a Fallen Princess, and quickly realizes that, despite thinking Regina was an unholy monster for the way she manipulated people, she herself cannot resist the temptation of raw power and admiration that the "Queen Bee" commands.
Her successor in the sequel is Mandi, without any redeeming qualities. She even goes as far as stealing from a charity in order to frame the protagonist. Jo Mitchell also becomes an Alpha Bitch after her Face-Heel Turn.
Subverted — Cher Horowitz is unquestionably one of the most popular girls in school, but she's also a genuinely nice person (if a bit spoiled, shallow, and airheaded).
Her rival, Amber Mariens, is a bit closer in spirit to the Alpha Bitch, but is less popular than Cher, and her sluttiness and airheadedness make her more like The Brainless Beauty (albeit a mean-spirited one).
In The Movie of Diary of a Wimpy Kid, Patty Ferrell was beginning to show the first signs of Alpha Bitch-itis. Granted, she was likely to evolve into an Alpha Bitch in the books and webcomics, but the movie definitely showed more of this.
Chloe from God Bless America is heavily implied to be this. Pretty, blonde, popular, rich, mean. Lines Such as "Everyone loves me because I'm so pretty". And Roxy, who's a Social Outcast is thrilled when she has her Karmic Death.
Mandy Moore's "Stupid Cupid" (the singing cheerleader, Lana Thomas) in The Princess Diaries. Notable mainly for the fact that director Garry Marshall explicitly pointed out that Lana was this on the DVD's supplemental material. She does, however, get a Break the Haughty moment when Mia deliberately squishes an ice cream cone on her chest and gives her a "The Reason You Suck" Speech. Not only do the principal and several teachers who were sitting near the scene not do anything (a true sign of how much she's really hated) but the other students cheer Mia on.
Amber Von Tussle in Hairspray, played by Colleen Fitzpatrick in the 1988 version, and Brittany Snow in the 2007 version.
Heather Chandler (and later Heather Duke) in Heathers. Played a bit non-standardly, because the protagonist isn't her unpopular rival but a member of her Girl Posse, albeit an increasingly uncomfortable one.
Sharpay Evans in High School Musical fits the part pretty well, but the movies' upbeat tone means that she's always redeemed by the end (yes, in eachmovie.) Though she's a somewhat unusual Alpha Bitch in that a) she's ruthlessly determined about being the star of the school play rather than prom queen, and b) she's actually unpopular for her behavior, apparently having no friends besides her brother Ryan, though this doesn't seem to bother her.
Meredith Baxter Dimly in Bratz: The Movie
Jane Mitchell in Zapped!, who gets a Carrie comeuppance in the end.
Also inverted with the character Enid, who fits all the Cool Loser points - apart from being a bully to some of her meeker classmates, being a Know-Nothing Know-It-All and being rude to Elle for no reason at all apart from assuming Elle would be a bitch to her behind her back.
Played with Betty Rizzo, who's the Alpha Bitch of the school, but is also the "bad girl" and so is her Girl Posse, nicknamed "the Pink Ladies" (except for Frenchie, who's more of a Na´ve Everygirl). She doessoften up a bit in the end, though, after she believes she's pregnant and almost falls out of grace..
Goody-goody head cheerleader Patty Simcox also has a bit of an Alpha Bitch streak in her; she gets an Alpha Bitch-style comeuppance at the school dance, when Kenickie throws her skirt up in front of everybody. Patty's really just there to illustrate the societal fault lines of 1950s high-school life. To the faculty and the "good kids," she is a pretty cheerleader and model student; to the "rebel" kids like the T-Birds and Pink Ladies, she is a Nerd, and thus eligible for all kinds of torment. (Recall that Kenickie puts a dead frog in her sack lunch to prank her, when Patty hadn't even done anything to him!) The character isn't really intended to be sympathetic, but any Alpha Bitch qualities Patty has might just be a defense mechanism against being picked on herself. (Interestingly, her Spear Counterpart, Eugene Feldsnick, has no morally objectionable qualities at all, and is even a Hidden Badass.)
Worst of all is Cha-Cha DeGregorio, who doesn't even attend Rydell High and is brought to the dance by Kenickie purely out of spite after he temporarily falls out of favor with Rizzo. While Cha-Cha isn't a snob in the traditional sense (obviously lower-class and the moll for the Scorpions street gang, who are so nasty they make the T-Birds look wholesome), she is very full of herself and determined to win the dance contest no matter what the cost to anyone else. In fact, Danny Zuko comes dangerously close to the Moral Event Horizon (in Sandy's eyes, at least) by abandoning her during the dance-off so he can win the trophy with Cha-Cha.
Elena in the Italian film A Game for Girls is a particularly dark example. She spends most of the movie as a typical Alpha Bitch, but when her idealistic new teacher tries to get her to change her ways, she conspires to frame him for rape, with herself as his victim, getting her own father killed in the process. And she gets away with it.
Harriet Bentley in Wild Child is a rare example. She's the "head girl" of the boarding school, and often fights with the rich Californian protagonist Poppy. She goes so far that she caused a fire and made Poppy friendless. At the end, she is expelled and humiliated by her former sidekicks.
Deconstructed beautifully with Claire in The Breakfast Club. Complete with Freudian Excuse. Particularly interesting about the deconstruction was how they pointed out that the Alpha Bitch is really not the one in charge at all, and she feels miserably forced into the behaviour she is so notorious for.
Frankie in The Hole, or so she's presented in the first version of Liz's story anyway, and Liz is far from being a reliable narrator.
Subverted in 16 Wishes. Krista Cook acts a great deal like the typical Alpha Bitch, but at the end, it turns out that she just held a grudge against Abby for stealing her best friend when they were children and wasn't mean to anyone but her. The two eventually reconcile.
Wendy from Prom Night is this right from childhood as she manipulates a group of other kids to keep an accidental death of one of their classmates a secret. She grows up to be a very straight example of this as she's openly jealous of Kim being voted Prom Queen and taking her boyfriend. She then attempts to win her man back and sabotage the prom.
Kelly from Hello Mary Lou: Prom Night II is a deconstructed example of this, with access to over a hundred dollars and very popular with everyone at school except main protagonist Vicki and friends. When they're both up for Prom Queen, Kelly proceeds to be as much of a total bitch to Vicki as she possibly could, even making fun of her dead friend. However, her snide remarks are reserved for her rivals, one of whom belittles her. She attempts to bribe the school computer geek to rig the voting tally. Reading his typed price of fellatio, she seems genuinely hurt. On later finding out she went through with it for nothing, her look of humiliated rejection implies an insecure girl who just wanted some adulation.
Mary Lou herself is another extreme example, starting out by cheating on her prom date at the prom in 1957, and after she's killed, she manipulates Vicki 30 years later by stealing her body and her boyfriend, killing many people in the process, all as a way to become Prom Queen again.
Madison Penrose in My Super Psycho Sweet 16 is bad enough that, at the end of the film, Final Girl Skye locks her in a basement with the killer because she feels that there isn't any discernible moral difference between the two.
Penny Lent in Sky High, captain and sole member of the cheerleading squad. She treats the sidekicks like servants, but Will is instant awesome after his fight in the cafeteria.
Danielle in The New Guy is an inversion in that, while being popular, head of the cheerleading squad and equipped with a Girl Posse, she's also brunette, not rich at all, and a genuinely nice person.
Brooke in Kick-Ass 2, who initially tries to help Mindy and remake her into a minion only to start bullying and humiliating her as soon as she accidentally proved herself a threat to her dominance over the school. Given that she bullied Mindy aliasHit-Girl, she got off easy when she was forced to puke and crap herself in public instead of being brutally murdered.
Taffyta Muttonfudge from Wreck-It Ralph, like everyone else in Sugar Rush, treats Vanellope's glitching as a glaring defect and bullies her profusely for it, appearing with the other racers to destroy her ad-hoc kart then later sabotaging the track to stop her from winning the race. She quickly defrosts when the game is reset.
The high school from GBF has three: Fawcett, who rules the popular kids, Caprice, who rules the minorities and performers, and 'Shley, who rules the conservative religious students. All three wield considerable influence among the student population. Subverted, though, as they are all Lovable Alpha Bitches to different degrees.
In Barbie Mariposa, Rayna and Rayla constantly demand Mariposa do their hair and dresses, send Willa off to get thistleburst which grows only in a stinky swamp, and obsess over looks and marrying the prince. They grow selfless through the course of their adventure, though.