Warning: The following feature contains SPOILERS for The Flash, season 6, episode 10, "Marathon."
The first episode of The Flash following Crisis on Infinite Earths revealed that the newly-reborn Arrowverse has more trouble than ever; luckily, Cisco Ramon has a binder full of villains charting it all. With several Earths having merged together post-Crisis, Earth-Prime is facing a sudden surge in its supervillain population and information on all of the bad guys is in short supply.
This would be bad enough, but as far as Cisco Ramon can tell, none of the heroic doppelgangers of Earth-1's heroes survived to be reborn on Earth-Prime to face off against their old arch-enemies. Worse yet, some of Earth-1's supervillains have reportedly come back from the dead with new or altered powers, and others have seemingly disappeared off the face of the Earth. Faced with a staggering amount of changes to the world he knows, and his powers no longer working (due to there no longer being a multiverse to breach across) Cisco has made it his mission to start gathering intelligence on every potential threat to Earth-Prime
While a binder full of self-designed supervillain trading cards might seem like a ridiculously low-tech way of tracking such important information, it is true to Cisco's geeky roots. It's also a sneaky tribute to DC Comics' Who's Who In The DC Universe; a comic book encyclopedia series which ran throughout the 1980s and into the 1990s, revealing the new history of the post-Crisis DC Comics universe. The following list is a rundown of every villain profiled in Cisco's Who's Who Binder and all the other villains and evil organizations he singled-out by name while discussing the new threats to Earth-Prime.
Abra Kadabra
A time-traveler from the 64th century of Earth-19, Citizen Abra violated his Earth's rules against breaching to other dimensions and many other laws besides. An unrepentant murderer and thief, Abra armed himself with advanced nanotechnology implants which allowed him to perform a variety of feats that appeared to be magic by the standards of 21st century Earth-1 science. He claimed to be one of The Flash's greatest enemies in the future, when Barry Allen faced him for the first time in the The Flash season 3, episode 18, "Abra Kadabra." The episode ended with Abra being taken back to Earth-19 to face execution for his crimes, but apparently the Crisis allowed him to cheat death... just like magic.
Amunet Black
Once a flight attendant named Leslie Jocoy, Amunet Black gained the power to magnetically manipulate certain iron alloys following the explosion of STAR Labs' particle accelerator. She adopted the alias Amunet Black and set herself up as a crime boss in Central City's underworld, specializing in metahuman trafficking and advanced technology. Ever the business woman, she agreed to help Team Flash in their battle against The Thinker, providing them with a weapon capable of disabling the satellites powering his Enlightenment. She disappeared from Central City after that, but the previews for The Flash, season 6, episode 11, "Love Is A Battlefield," indicate she's about to make a comeback.
Block
A weapons dealer for the East Street Skulls gang, Vanessa Jansen gained the power to create super-dense boxes of compacted air molecules after STAR Labs' particle accelerator exploded. Given the codename Block by Cisco Ramon, Jansen was wounded by the metahuman serial killer Cicada after Team Flash had subdued and arrested her in The Flash, season 5, episode 2, "Blocked." Despite Team Flash's best efforts, Block died before they could get her to the hospital in the Pre-Crisis timeline.
Bug-Eyed Bandit
A brilliant mechanic engineer employed by Mercury Labs, Brie Larvan created a mechanical bee capable of pollinating plants for agricultural purposes. Unfortunately, Larvan was of a more mercenary mindset than her bosses, and was fired after she began exploring unauthorized military applications for her work. As the Bug-Eyed Bandit, Larvan sought revenge on the co-workers who turned her in for misappropriating company resources and tried to steal an experimental bio-chip from Palmer Technologies. After facing defeat at the hands of both Team Flash and Team Arrow, Larvan joined up with the Young Rogues to rob McCulloch Technologies, but didn't prove to be any better as part of a criminal gang than she was as a solo act.
The Dominators
The Dominators are a telepathic alien race known for their love of conquest and experimentation on the inhabitants of other planets. The Dominators lay siege to Earth-1 during the Invasion! crossover event and demanded the execution of all metahumans, whom they saw as an obstacle to their expansion across the galaxy. The Dominators were also a major threat in the reality of Earth-38, where they helped facilitate the intergalactic slave trade and worked with the villain Roulette to abduct Earthlings who would not be missed.
Girder
A steel-factory worker with a history of violence and petty criminal activity, Tony Woodward was also Barry Allen's childhood bully. The particle accelerator explosion at STAR Labs just happened to occur as Woodward fell into a vat of molten steel while attacking the supervisor who informed him that he had been laid off. This left Woodward (who was later dubbed Girder by Cisco Ramon) with the power to transform any part of his body into solid steel. He was later killed by the villain Blackout, whom he was tricked into fighting by the Reverse Flash, in the Pre-Crisis reality.
Grodd
Grodd was once an ordinary gorilla and test subject at STAR Labs. His mind was enhanced by the particle accelerator explosion, giving him enhanced intelligence and incalculable psychic powers. Grodd went on to menace Central City on multiple occasions and joined forces with sorcerer Damian Darhk to fight the Legends of Tomorrow. Grodd's current whereabouts are unknown, but his psionic abilities were said to be growing stronger when he was last taken into ARGUS custody following a battle with King Shark.
The Hotness
Jaco Birch was an ordinary Central City citizen who just happened to be on the scene of a battle between pyrokinetic bank robber Eric Fyre and EMT Matthew Kim, who thought he had developed the power to take away the metahuman abilities of other people. In truth, Kim had the ability to transfer metahuman powers from one person to another, rewriting their DNA with a touch of his hand. Kim accidentally gave Fyre's power to generate flames at will to Jaco Birch, prompting Birch to go on a short-lived crime spree as The Hotness. He was quickly brought to justice by Iris West-Allen, who briefly assumed the duties of The Flash after Kim accidentally gave her Barry Allen's super-speed.
King Shark
Originally a marine biologist on Earth-2, Dr. Shay Lamden underwent a horrific transformation following the destruction of STAR Labs' particle accelerator, taking on the characteristics of a shark. Left in a savage state and dubbed King Shark, Dr. Lamden was a perfect minion for the villain Zoom and his war on Earth-1. He later acted as a test subject for Cisco Ramon's metagene cure during The Flash season 5, but ultimately sacrificed his humanity to save Central City from Gorilla Grodd.
Magenta
Frankie Bridge was an orphan who had been bounced from foster home to foster home. A lifetime of abuse caused Frankie to develop a dissociative personality disorder and a second persona called Magenta, which was given the power to magnetically manipulate metal by the villain Alchemy. Magenta attempted to kill Frankie's abusive foster father, but was thwarted by Team Flash. Frankie was later moved to a different foster home, with STAR Labs offering to help her if her Magenta personality ever emerged again.
The Mist
A hit-man for the Darbinyan crime family in Central City, Kyle Nimbus was the third metahuman villain Barry Allen fought as The Flash. Scheduled for execution for his crimes on the night of STAR Labs' particle accelerator explosion, Nimbus' body bonded with the hydrogen cyanide filling the gas chamber. This left Nimbus with the power to transform himself into a living cloud of toxic gas and a more efficient killer than ever as The Mist. He could be anywhere on Earth-Prime, having disappeared from Central City following his escape from STAR Labs in the season 1 episode "Rogue Air."
Null
One of the dozen "bus metas" created by The Thinker as part of the plan to bring about his Enlightenment, Janet Petty was a career criminal who gained the power to manipulate gravity. Petty was able to give The Flash the runaround in the episode "Null and Annoyed" but was ultimately brought down by Elongated Man. Sadly, Team Flash was unable to protect her from The Thinker, but there is apparently reason to believe she might have been reborn on Earth-Prime.
Dr. Kimiyo Hoshi
Described in Cisco's Who's Who Binder as a Japanese astronomer who disappeared four years before Crisis on Infinite Earths, Dr. Kimiyo Hoshi was said to have the metahuman ability to generate enough energy to fuel a star, but no way of safely expelling that power. She apparently found an outlet for her abilities through the sinister group known as the Black Hole, who armed her with an experimental photon rifle stolen from McCulloch Technologies. Using her own bio-energy as a power source, this new Dr. Light can vaporize anything (or anyone) in seconds.
Trickster
The son of the original Trickster and his partner, Prank, Axel Walker attempted to follow in the footsteps of his criminal parents. As the new Trickster, Walker fought against Team Flash on two occasions, teaming with both his father and his mother to spread chaos across Central City with toy-based weaponry and deadly deathtraps. He was last seen being taken to Iron Heights Penitentiary, so there's no reason to believe he isn't still somewhere on Earth-Prime, planning to pull another fast one on The Flash.
Ultraviolet
Part of a family of career criminals, Esperanza Garcia was in Central City Juvenile Hall when STAR Labs' particle accelerator exploded. The accident awakened Esperanza's metagene, giving her the power to manipulate a variety of energies across the electromagnetic spectrum. Her trademark maneuver, which earned her the moniker of Ultraviolet and nearly flash-fried Barry Allen, involves baking people to death with focused blasts of UV radiation. An assassin in the employ of the mysterious Black Hole organization, she was last seen being taken into custody after acting as muscle for German crime boss Remington Meister in "License to Elongate."
Weather Witch
The estranged daughter of career criminal Mark Mardon, Joslyn Jackam seemed to have overcome her resentment of her circumstances and abusive parents to become a skilled amateur meteorologist. However, when her weather van was destroyed on the night of The Thinker's Enlightenment, Joslyn seemed to become obsessed with getting revenge on her father and proving herself his superior. Utilizing a meta-tech staff to control the weather, Joslyn dubbed herself the Weather Witch and joined forces with Silver Ghost and the Young Rogues when her solo efforts to fight The Flash failed. She was last seen during Crisis on Infinite Earths, where she was foolish enough to pick a fight with Supergirl.
Weather Wizard
Mark and Clyde Mardon were an infamous pair of bank-robbing brothers in Central City. Making their escape from their latest crime by airplane, the two became caught in a storm as STAR Labs' particle accelerator exploded. Both brothers gained the metahuman power to control the weather and Clyde became the first metahuman criminal Barry Allen fought as The Flash. Later, Mark Mardon sought to avenge his brother's death at the hands of Detective Joe West and was dubbed the Weather Wizard by Cisco Ramon.
The Top
Rosa Dillon and her boyfriend Sam Scudder were part of Leonard Snart's gang one year before he became Captain Cold. Both she and Sam were empowered by the explosion of STAR Labs' particle accelerator, with Rosa gaining the power to induce vertigo in other people by making eye contact with them. This left them seeing the world spinning, leading her to be dubbed The Top by Cisco Ramon.
Eden Corps
Led by a woman named Veronica Dale, the Eden Corps was a militant eco-terrorist group, determined to to stop human industrialization through violent upheaval. The Eden Corps nearly destroyed Central City with a nuclear bomb in The Flash, season 4, episode 15, "Enter Flashtime." Though the entire group was believed arrested in 2018, they resurfaced in the year 2040, backing a plot to bomb Star City. Their current status on Earth-Prime is unknown.
Rainbow Raider
Another career criminal empowered by the explosion of STAR Labs' particle accelerator, Roy G. Bivolo was initially dubbed Prism by Cisco Ramon. He later took the name Rainbow Raider for himself, based on how his ability to manipulate the emotional states of other people was reflected by his eyes flashing red when he used his powers. During his two battles with The Flash, Roy didn't show any aptitude for inspiring emotions other than rage. It seems possible, however, that Roy may have branched out into inspiring fear or depression with his powers (like his comic book countepart) in the new Arrowverse.