Caitlin's mother Dr. Tannhauser runs some tests on her cold powers in episode 3x05 "Monster".
Barry and Wally go to stop Ramsey Deacon but he manages to take control of Barry's fancy new suit in episode 4x02 "Mixed Signals".
Vanessa Jansen crushes Bobby Moretti into a tiny cube and steals his guns. Nora shows up when Barry is investigating the scene and he has to pass her off as his new intern to Captain Singh in episode 5x02 "Blocked".
Cicada changes into his work clothes and thinks back to the murder of Gridlock earlier in the evening in episode 5x02 "Blocked".
The new Rogues infiltrate the secure weapons testing lab but the others turn on Nora and hold her hostage to draw out the Flash in episode 5x20 "Gone Rogue". Nash guides Barry and Cisco to the vault where the cure-all syrum is stored in episode 6x04 "There Will Be Blood".
The other members of the gang run by the smuggler Ramsey killed are attacked at night by their dead boss in episode 6x03 "Dead Man Running".
Frost and Barry try to stop Mitch Romero when he attacks another lab but they learn he cannot be killed when Frost throws him out a window in episode 6x03 "Dead Man Running".
Ramsey remembers his mother when he learned that she was sick in episode 6x04 "There Will Be Blood".
The team tracks down Laura Washington who stole the device they need to use the alien tech and Rene confronts her with Barry & Kara in episode 5x08 "Invasion!".
Diggle and the team attempt to foil a robbery of some medicine only to find the thieves are Bratva led by Anatoly and sent by Oliver in episode 5x18 "Disbanded".
Oliver leads the team in stopping Anatoly's second medicine heist in episode 5x18 "Disbanded".
Felicity and Curtis break into a tech company to steal the tool they need to decrypt Chase's image scrambler in episode 5x18 "Disbanded".
Oliver, Anatoly, and the Bratva break into a medical company to steal some medicine for the sick children in episode 5x18 "Disbanded".
Black Siren breaks into a lab under the guidance of Cayden James and steals some Nano-Termite in episode 6x07 "Thanksgiving".
The team tracks Black Siren to a second robbery but Diggle has a medical incident during their attempt to stop her in episode 6x07 "Thanksgiving".
Dr. Collier joins the CDC team investigating the zombie virus and is assigned as liaison to Ravi in episode 5x01 "Thug Death". The team comes up with a plan for sneak into Dr. Saxon's private vault and steal the formula in episode 5x12 "Bye, Zombies".
Liv brings the badge out to Ravi and discusses splitting the loot in episode 5x12 "Bye, Zombies".
A group of researchers in the arctic find a frozen wolf body and something goes terribly wrong when they go to dissect it leading to the D.E.O.'s investigation in episode 2x06 "Changing".
Dr. Jones heads back to his lab after being rescued by the DEO and kills his boss who wants to fire him in episode 2x06 "Changing".
James interrupts a deal between Brian and his drug dealer and squeezes some information about the attack on the square from him in episode 2x20 "City of Lost Children".
James, Winn, and the alien refugees leave their hideout to watch the spacecraft flying over the city in episode 2x20 "City of Lost Children".
Kara finds Thomas Coville beneath the stadium with the Kryptonian pod set to detonate in episode 3x04 "The Faithful".
Source: What's Filming
Kara arrives at a robbery by the Children of Liberty in time to save Manchester from being shot in episode 4x07 "Rather the Fallen Angel".
Lex supervises a series of tests of Snowbird's strength and abilities in episode 4x16 "The House of L". Kara and Lena find the base deserted except for a bunch of paper files and Eve acting very oddly in episode 4x20 "Will The Real Miss Tessmacher Please Stand Up?".
Kara and J'onn track Rip Roar to a base in Antarctica but are unable to stop him from punching a hole in the ice cap in episode 5x05 "Dangerous Liaisons".
Kara tries to stop Rip Roar from enhancing the Marathon Laser but he hits her with it and escapes in episode 5x05 "Dangerous Liaisons".
Alex is taken by her teenage self to the last place she saw her father in an effort to get her to confront her reality in episode 5x16 "Alex in Wonderland".
Mouse sneaks in to the lab in the guise of the chief scientist, tricks Catherine, and steals the prototype in episode 1x06 "I'll Be Judge, I'll Be Jury".
Kate searches the only warehouse in town that stores Hydrogen Cyanide pellets but isn't able to stop the Executioner's theft after being hit by his truck in episode 1x06 "I'll Be Judge, I'll Be Jury".