Alpha Bitch Michaels of Clifford Odets's Paradise Lost. In typical Odets fashion, she gets some interesting and dark depth: initially the frivilous fiancée of the Gordon family's athlete son Ben, she dumps him for his slimy social-climber "friend" who gets Ben fatally injured.
Lucy in 13 is the stereotypical Alpha Bitch, but she's only second in command after The Brainless Beauty Kendra.
Amber Von Tussle from Hairspray. She learned it from her mother Velma, who is an Alpha Bitch grown up. They both get better at the end though.
Adrian in The Shape of a Girl.
Heather Chandler from Heathers is the cruel, domineering, vain and manipulative "demon queen of high school." After she dies, Heather Duke takes over. At the end, Veronica kicks Duke out of her position, and is determined to make the school less horrible for people who are different, though she admits, "I can't promise no more Heathers."