Barry is attacked by the shark-man and is saved by Harrison Wells when Patty's gun is insufficient for the job in episode 2x04 “The Fury of Firestorm”. The police fight against the meta-humans under Zoom's control in episode 2x22 “Invincible”. Nora and Barry meet with Joss Mardon to trick her into handing over her staff using a hologram of her father in episode 5x07 “O Come, All Ye Thankful”.
Cisco has a vision of birds crashing into the ground on Earth-2 in episode 2x22 “Invincible”.
Cisco travels to Earth-19 where Cynthia Reynolds is reporting on the success of her latest assignment and tries to get her to return to help on Earth-1 in episode 3x14 “Attack on Central City”.