We first begin to see the Girls Underground archetype really take shape in early fairytales and folktales. More developed than the mythological versions, these stories have detailed elements of the plotline.

Snow White

A beautiful girl envied by her evil stepmother is saved from death by a kind-hearted servant but nonetheless cast out into the wilderness alone. She then meets a strange group of creatures, dwarves, who shelter her. But the adversary comes, disguised, to trick her into eating a drugged apple, at which she falls into a death-like sleep and is prepared to be buried. However, just in time a prince comes and miraculously saves her, and punishes the stepmother horribly for her wickedness. (The best film version of this is Snow White: A Tale of Terror starring Sigourney Weaver.)

Beauty and the Beast

Developed from the older Cupid & Psyche tale. An older girl enters the otherworldly Beast's castle as a prisoner willingly in order to save her father from his foolish mistake. She roams the castle's many halls and rooms alone, but has to face the Beast nightly and do as he wishes. She has portentous dreams and receives a magic mirror that allows her to see her sick father at home. When she is permitted to go to him, she finds that the Beast is dying without her presence. She must rush back to his side and give him the love that will make him human again. (I admit to being a fan of the old Beauty and the Beast television series with Ron Perlman.)

Bluebeard / The Robber Bridegroom / Mr. Fox / Fitcher's Bird

There are many many variants of this story, but basically a woman is engaged to or marries a man who is revealed to be a murderer. When she discovers his grisly secret, she must escape before he murders her as well. In Bluebeard she is rescued by her brothers, but in the other stories she uses her own cunning to reveal him, and then he is killed by her family. 

Hansel and Gretel

Seen from Gretel's perspective, this story fits the archetype. Cast out by their cruel parents, she and her brother (as companion) venture into the woods alone, only to be tricked and captured by a witch. However, Gretel manages to turn the tables on her adversary, rescue her brother, and escape.

The Seven Ravens / Six Swans / Twelve Brothers

A girl's many brothers are transformed into birds, and she must rescue them through a series of difficult tasks (a journey to dangerous lands, keeping silent for years, sewing shirts from nettles, etc.). She is sometimes helped by a dwarf. (A beautiful version of this is Daughter of the Forest by Juliet Marillier.)

Other folktales with elements of the Girls Underground storyline include Tam Lin, Little Red Riding Hood (see Freeway, The Company of Wolves, and  Red Riding Hood for some interesting film adaptations of this story), Rumpelstiltskin, and The Handless Maiden.