Barry is attacked by the shark-man and is saved by Harrison Wells when Patty's gun is insufficient for the job in episode #204 "The Fury of Firestorm". The police fight against the meta-humans under Zoom's control in episode #222 "Invincible".
Diggle follows Moira to a covert meeting with Malcolm and overhears part of it in episode #113 "Betrayal".
Laurel rants about her father spying on her to Tommy who gets mad about her talking to The Vigilante in episode #113 "Betrayal".
Diggle finds one of the virus carriers at a downtown plaza who is then taken out by Thea in episode #323 "My Name Is Oliver Queen".
Oliver meets Merlyn in a downtown square in episode #304 "The Magician".
Kendra and Carter part ways with the group and Oliver and his crew get ready to head back to Star City in episode #408 "Legends of Yesterday".