This lists is a small and eternally incomplete selection of minor villainesses who never made it to be big leagues. Thanks to their often short-lived careers, these characters can give writers the opportunity to explore themes that might not suit characters meant to become part of the established cast of major characters.
As a rough guide I've tried to limit the selection to characters who have appeared in less than a dozen or so issues.
Scheme: Harmony was a member of the Order of the Scythe who was sent to retrieve DNA samples from an abandoned convent.
Career end: Harmony is defeated by Batgirl and incarcerated at Blackgate Penitentiary. The Order later attempts to free her and other members, but they are confronted by Batgirl and her allies before they can escape. The other members attempt to fight the heroes, but Harmony surrenders.
Scheme: Vapor was a surgeon who extracted eggs from a former Weapon X project called the Native.
Career end: Vapor was killed by Wolverine.
Scheme: Tramma has been involved in various plots related to medical and robotic enhancements.
Career end: -
Scheme: Yavana wants to awaken the dragons of the Silent Grove, and needs the blood of King Alistair to do so.
Career end: Yavana was seemingly killed by King Alistair.
Scheme: Devon was the second in command of a group that attempted to kidnap a large number of civilians and hold them hostage.
Career end: Devon was killed and briefly impersonated by the hero Mantra.
Scheme: Smoke Scream was a henchmen of Mad Dog, who attempted to destroy the S.H.I.E.L.D. organisation.
Career end: Smoke Scream was killed by Psi-Borg.
Scheme: The Duchess of Mklavia wanted to regain the throne of Mklavia.
Career end: She was betrayed and killed by her second in command, Iron Klaw.
Scheme: Lady Coffin was the leader of a corporation specializing in organic technology and cybotic-ambiosis.
Career end: series discontinued.
Scheme: The Red Queen led a group involved in basic crimes for financial gain.
Career end: Her involvement in the story ends when her henchmen are chased off after pursuing the protagonist to Astro City.
Scheme: Baroness Krieg attempts to incite a war between India and China, for which she will supply the weapons. The ultimate goal being to grab power once the two countries have weakened each other.
Career end: She was defeated by the X-Men and handed to the local police.
Scheme: Insect Queen is an alien sent to Earth to establish a colony of her own. She develops a special interest in the Kryptonians.
End of career: Insect Queen is trapped in suspended animation by Superman and seemingly destined to roam the galaxy for eternity. She later reappears and confronts Supergirl, revealing that she was able to transfer her consciousness into Lana Lang's body. Supergirl eventually expels her from Lana's body. Whether her consciousness has transferred back to her body floating in space, or that Supergirl has effectively killed the Insect Queen is unknown.
Scheme: Pythonia seeks to usher in an age ruled by Cobra-La. She keeps Joseph Colton, the original G.I. Joe, as a pet in her dungeons.
Career end: Pythonia grows to respect Colton, and when the Cobra-La meet the G.I Joes & Transformers in battle she surrenders. It is said that she and other prisoners will stand trial for crimes against humanity.
Scheme: Valerian is the daughter of Emperor Herus Chimeran. She and his other children are sent to retrieve Sigil bearer Sara Janning so that the Sigil's powers can be investigated and used to the Emperor's benefit.
Career end: Though successful in capturing Sara Janning, the Sigil gives Sara the power to awaken from her induced coma. Valerian is killed in the resulting explosion of the starship.
Scheme: Ubiquitor had spend countless ages destroying universes. When her Emissaries failed to destroy the Galactic Guardians she sought to eliminate them herself.
Career end: Phoenix IX and Woden channelled their combined forces through Mjolnir and were seemingly able to banish Ubiquitor, but whereto is unknown. It is also possible that she was killed, as the last panel in which she appears features the quote 'All our yesterdays have lighted fools the way to dusty death, Macbeth'.
Scheme: Scarab is an Assassin for hire who was contracted to kill Red Robin. She wears an advanced suit, which turns out to be highly vulnerable to electromagnetic pulses.
End of career: Scarab is defeated by Red Robin and sent to prison. Later on, Red Robin enlists her aid to track down the Covenant of Ka, but he ends up betrayed by Scarab. Red Robin, with the aid of Cassandra Cain, eventually manages to knock her out. It is unknown what happens to her afterwards.
Scheme: Server Aja is the daughter of a Chinese billionaire. Together with other rich young metahumans she went on a crime spree on Father's Day, to make a point.
End of career: Server Aja was freed from police custody by Kestrel, an agent of the Lords of Chaos. The power he gifted to Aja turned her into a near mindless slave. What happened to her after Kestrel's defeat is unknown.
Scheme: Primaid was one of the leading Martians who attempted to invade and conquer Earth.
End of career: Primaid and the other Martian invaders were defeated by the JLA.
Scheme: Blue Moon derived her powers from Earth's moon. She used these powers in her work as a mercenary.
End of career: Blue Moon was defeated by Power Girl and, presumably, taken into custody.
Scheme: Elinor was a creature of darkness who feasted on the living. She gathered a group of darklings to serve her needs.
End of career: Elinor was thrown into the sunlight by Ripclaw, reducing her to a pack of rats.
Scheme: An armsdealer with an elaborate power suit, she frequently faces off against the hero Critter.
End of career: -
Scheme: Miss Hexley was the assistant headmistress at St. Hadrian's Finishing School for Girls. She sold the school out to Leviathan, creating an army of assassin's for the shadowy organization.
End of career: Miss Hexley was apprehended by Batman with the help of Batgirl Stephanie Brown. Miss Hexley recently reappeared in the 2014 Grayson series.
Scheme: Mayfly was an highly skilled assassin hired to kill Wonder Woman. She had super-human speed, and was thought by some to be even faster than the Flash.
End of career: While in custody, Mayfly lost control of her powers. She crashed into a wall at high speed, killing her instantly.
Scheme: Cassie Arnold was transformed into a demon by her associate, the White Magician. She battled Wonder Woman at his behest.
End of career: It is unknown what happened to Cassie after the White Magician was killed.
Scheme: Mind Drainer could rearrange and remove memories, and attempted to so to the heroine Ant.
End of scheme: Mind Drainer was incapacitated in a block of ice by he heroine's sidekick, and hasn't been seen since.
Scheme: Gina DiMedici was a leader among the Puritans, a group of xenophobes who travelled back in time to eradicate all extra-terrestrial life from earth.
End of career: The Puritans are defeated, and a clash with Max Cash of the WildC.A.T.S leaves Gina unconscious. Her time-travelling Chrono-Beacon is then stolen, leaving Gina stranded on a prehistoric earth.
Scheme: Arcana is an alien intent on eradicating all life on Earth.
End of career: Arcana is confronted by her half-human half-sister, and in the ensuing battle Arcana is knocked unconscious (and possibly killed). Her half-sister then attempts to destroy the device Arcana planned to use to destroy all life on Earth.
Scheme: Mercenary information broker and metahuman, Axis and her fellow members of Dark Nemesis work for anyone who is willing to pay their high fees.
End of career: Axis fought the Teen Titans and Titans and was briefly imprisoned in The Slab. After another confrontation with the heroes ends in defeat she is imprisoned again. She hasn't been seen in action since.
Scheme: Mystress was the leader of a Rhormorid battle fleet that had conquered multiple worlds. She went to Earth to rejuvenate before her next big conquest.
End of career: Her plans to syphon the energies of some of Earth's heroes was thwarted. In the battle Mystress tripped and fell into an explosion. She somehow survived, unbeknownst to the heroes, but by the time she resurfaced the Rhormorid battle fleet had returned to deep space, presumably leaving her stranded on Earth.
Scheme: Crimson was a vampire who tried to seduce Archangel and convert him to one of her race, known as the Ravens.
End of career: Her fight with X-Factor eventually ended in her death.
Scheme: Sinn kidnapped Harley Quinn and sought to eliminate her gang.
End of career: Harley Sinn was briefly incarcerated at Arkham Asylum but was recently freed (ongoing story).
Scheme: Sister Blood sought to infect humans with Beast Boy's blood, presumably in order to control them.
End of career: After barely a fight, the Teen Titans knock her unconscious and unceremoniously dump her on a pile of her defeated henchmen. She was presumably arrested.
A member of the Dark Riders; she was killed by shrapnel flung across the room when Wolverine forcefully expelled his adamantium implants.
