Caitlin is out for a walk with her father when he collpases and she sees his icy skin in episode 5x06 "The Icicle Cometh".
Quentin and Julia use a device they've taken from Brakebills to travel back to 1942 to use one of the Fillory entrances in episode 1x12 "Thirty-Nine Graves".
J'onn poses as Alex to draw out the killer in episode 3x20 "Dark Side of the Moon".
Kiera is memorializing Lucas with Alec when Brad approaches them, and later Keira meets with Brad and gets the storage locker address in episode 4x04 "Zero Hour".
From episode 1x01 "Where Paradise Is Home".