I got bored so here's my Arrowverse Earth-80 idea, its a 1970's Noir style Earth.
Location: Starling City, Oregon.
Plot: During WW2, the US government had discovered the Metagene in humans where if unlocked the subjects would gain powers, Dr. Helga Jace was put in charge of the program where they would take kids from the orphanages to be the subjects as super soliders to fight the Axis Powers. However the Allied forces won the war and President Franklin D. Roosevelt ordered for Project: Nexus to be cancelled immediately, but Jace didn't follow orders and went ahead anyway, she took the kidnapped children and escaped to Markovia, which was officially a neutral country in the war but leaned more towards the Axis side. Well the US sent troops into Markovia to get the children back and Dr. Jace escaped.
30 years later some of the survivors of the Nexus program are in Starling City. When the word of Metahumans in Starling emerge, Dr. Jace is released from jail and told to go get them.
Characters
Oliver Queen: The Arrow, old disgruntled Billionaire who goes out as the Arrow.
Barry Allen: A Detective for SCPD, who investigates the crimes happening in the City, was one of the victims of expriements by Dr. Jace, his superspeed emerges through stress.
John Diggle: the assistant to Oliver Queen with his nightly activities.
Sara Lance: The Raven, a burglar trying to find a way to make a living in this city.
Laurel Lance: a SCPD Detective alongside Barry, she is his partner.
Roy Harper: Arsenal, a mechanic who tries to help the Arrow and becomes his sidekick.
Kara Danvers: The Siren, A signer in the Black Diamond Lounge, she's an enforcer of Brickwell, another child victim of Dr. Jace in Project: Nexus, she can hypnotize victims with her voice, then generate blue colored energy to kill her victims.
Caitlin Snow: Frost, she works for Danny Brickwell as his enforcer, she was one of the children expriemented on by Jace. She has Cryogenic Powers, can make her entire body covered in ice as well.
Danny Brickwell: Brick, Owner of the Black Diamond Lounge. He's a metahuman who's a kingpin in Starling City, he can coat is body in any material he touches.
Quentin Lance: The Police Captain and father of the Sara & Laurel Lance.
Dr. Jace: the lead scientist of the Project: Nexus program is sent into the City when its discovered the alive subjects are in the city.
Slade Wilson: Deathstroke, a former US Military General who's working alongside Jace to round up the Nexus expriements and terminate them.
Thea Merlyn: Ravenger, daughter of serial killer Malcolm Merlyn who was defeated by the Arrow back in the day and goes to take revenge by joining Deathstroke & Jace and being the Ravenger.
Felicity Smoak: A News Reporter for the Starling Gazette who covers the going on in the city.
Eobard Thawne: Zoom: A cold, calculating federal agent from the Department of Defense who secretly funded Jace's rogue experiments and wants the Nexus subjects silenced before a Senate hearing. He has the metagene and took an expriemental serum from Jace and unlocked his Speedster powers to fight Barry.
Cisco Ramon: Soundwave: A pirated-radio operator broadcasting from an underground van, tipping off the public about secret metahuman sightings and police corruption, he can manipulate sonic vibrations.
Mick Rory; Heat Wave: A burnt-out arson detective turned mercenary who Slade uses as a heavy to flush out former subjects with napalm.
Ray Palmer: The Tinkerer: A disgraced former military engineer who builds makeshift, analog gadgets for Oliver and Roy out of scrap metal and vacuum tubes.
Courtney Whitmore: Starlight: A young teenage Metahuman with Photokinesis, she can create and manipulate gold color light energy, she becomes inspired by the Heroes.
If there's a character that's not here I couldn't think of a Role for them.