Toward the beginning of the gamen when you wake up as Tyler, there is a desk in the bedroom with an action figure. Examine it, and he will say "This is a figurine of Sox, a character from my favorite videogame." Sox is a robot from another game by Quantic Dream, Omikron The Nomad Soul.
Look at the following locations to find the corresponding number of tarot cards:
Lucas' apartment in the kitchen cupboard (5) Lucas' apartment on the balcony (10) Central Park in the alley on the right (20) Naser and Jones at a stall in the open space (5) Naser and Jones in a toilets box (10) Cemetery near Markus (5) Agatha's House in the kitchen (5) Agatha's House in the bathroom (20) Naser and Jones in Lucas' desk (10) Agatha's House in Agatha's bedroom (10) Tiffany's apartment in the street (20) The museum in the room (5) The Fun Fair near a fence (20) The Subway on the rails (20) Police Station in the hall (10) Police Station desk drawer (5) Gymnasium behind the ring (10) The Archives in the boxes near the locked door 10) Carla's Apartment in the bathroom (10) Police Station in the open space (20) The Lavomatic in the cart (10) Bellevue Asylum in the corridor (10) Tyler's apartment in the bathroom (10) Police Station desk drawer (5) Takeo's Shop on the first floor (20) Takeo's Shop near the stairs (20) Police Station in the open space (5)