With Oliver Queen (Stephen Amell) being sent to Slabside Super Max, this gives Arrow a chance to revisit some of their favorite villains from over the years. And if they are loosely adapting the Escape from Super Max screenplay, then they will definitely need some interesting villains for him to team up with. While they could just introduce new ones, I think it would be more fun to bring back a handful of the more intriguing ones from previous seasons.
Now, it takes a special kind of criminal to make it into a super max facility, so you're not going to see the white collar businessmen that the Green Arrow has gone after. It's got to be the hard case killers, assassins, and meta-humans. Here are a few of my favorites I'd like to see.
Double Down – Jeremy Tell (JR Bourne) was affected by the particle accelerator explosion and gained the ability create playing cards from the tattoos on his skin and then throw them with deadly accuracy. He was hired by Damien Darhk to take on the Green Arrow but was defeated by GA and Spartan, forced to give up what he knew about Darhk and HIVE, and sent to Iron Heights. It's possible that he would end up in Slabside at some point.
Sampson – Derek Sampson (Cody Runnels) was a drug dealer who was thrown into a vat of chemicals that caused him to lose his ability to feel pain but also gave him an accelerated healing factor as well as enhanced strength and endurance. He teamed with Prometheus for a short while to take on Green Arrow and to help release a weaponized form of Tuberculosis. He was defeated and sent to prison. He would seem like the perfect type of person to be sent to Slabside.
Anarky – Lonnie Machin (Alexander Colvert) is a highly trained fighter and assassin. He worked as a mob enforcer, hired to stop Jessica Danforth from running for mayor. When he is disfigured, he mentally loses it and becomes an anarchist, setting his sites on Damien Darhk and HIVE. His actions put him in conflict with Green Arrow and Speedy and eventually led him to trying to blow up Tevat Novah, the underground city Darhk built to house his new society after he dropped a nuke on Star City. He was beaten by Oliver and Thea and left for the SCPD.
Brick – Danny Brickwell (Vinnie Jones) was a gang leader with plans to take over the Glades. He had an almost impossible tolerance for pain, a well-trained brawler and marksman, and a strong leader and tactician. His plan lead him to conflict with Team Arrow and another street vigilante called Wildcat. But he was eventually bested by Malcolm Merlyn and left for the police. While in prison, he was released by Damien Darhk as part of a prison riot that lead to the death of Black Canary. He was likely recaptured along with the other prisoners after the riot.
Vertigo – Werner Zytel (Peter Stormare) was a drug dealer and crime boss who took on the Vertigo trade after the death of the Count. Zytel figured out how to weaponize the drug, causing hallucinations and balancing the playing field when he's in a fight. He's a skilled fighter, but his knowledge of chemistry makes him dangerous. He was arrested and incarcerated in his last appearance, making Slabside a possible location for him.
Komodo – Simon Lacroix (Matt Ward) is an archer, mercenary, and assassin who was believed to be Sara Lance's killer until he provided an air-tight alibi for the night. He was in Bludhaven killing someone else. He also killed people in Star City, which led to him being taken down and sent to jail. He hasn't been used much in the series and would be very interesting to spend more time with in the new season.
There are other fun villains that could be brought back like China White, Bronze Tiger, Mr. Blank, Murmur, and Clock King, but the above made the most sense to me story wise.
Arrow returns this fall on Mondays at 8 p.m. ET on The CW.