This page lists all locations of the cassettes/tapes that you can find in Chapter 2 of Poppy Playtime. Obtaining them won't unlock any achievement or reward. Some of them are purely optional, and taking them will only reward you with more lore.
Location: This tape is in the office, which you will get to after finding the key behind the white door. The tape is on a sturdy brown desk.
Light green tape
Location: The cassette is on the mechanism used to create a green hand. Just pick up the tape and use the TV set next to it to play it.
Location: Toy warehouse. The tape is on the ladder, in the first row from the right.
Location: Yellow tunnel where you have to move Barry's wagon. This tape is right next to the player that's the same color as her.
Location: This tape is in the center of the platform, right next to the door labeled Game Station.
Location: You can get this tape during the story mission. It is right next to the mechanism to which you need to connect the current beam.
Location: You can't miss this collectible. You'll find it right under your feet as you walk across the metal platforms at the very end of Chapter 2.