There are 42 collectibles in Gears of War: Judgment. Each one is a COG Tag containing personal information on a Gear and detailing how they died in Halvo Bay. One can be found in every chapter of the game.
From the level exit, turn around to see the COG spray behind a tree in a small park. The COG Tag is to the right near some trashcans.
After surviving the final wave of Boomers at the end of the level, run down the stairs to the right.
At the very beginning of the level, chainsaw through the door and look for the red COG spray on a building to the right. Follow the alleyway past some Frag grenades to find the COG Tag collectible.
In the water at the base of the fountain.
The COG Tag is directly underneath the mounted machine gun at the top of the small stairs.
The COG Tag is directly to the right of the exit door next to an Onyx Guard corpse.
After leaving the first section with the Serapede eggs, follow the left wall to find the red COG spray. The COG Tag is to the right of the spray.
Follow the edge of the E-Hole to find the collectible in the Vaults.
Near the mounted gun at the middle of the bridge.
As soon as you enter the school, go left into the office to find the COG Tag.
During the first section, you will see a few grubs bust through some windows on the right wall. The COG Tag is in that room.
Behind the desk in room 24 on the right side.
In the very first section of the level, the COG Tag is in a small room at the back right of the main room. NOTE: there is a second COG Tag you can pick up during this level (at the very end near the exit), but the second COG Tag counts towards the next level, Crash Site.
At the very top of the stairs on the right side (facing up). You can pick this COG Tag up at the very end of the previous level, Atrium.
Near the very end of the level, you will run up a few short sets of stairs. Look for the COG Tag at the top of the short stairs; there's a slightly longer set of stairs near the COG Tag that has an Onyx ammo case.
Near the exit of the level, run past the door to continue, and the COG Tag is on the left behind a small column.
The COG Tag is near the end of the level, out on the street you will see a few cars piled up and a fire hydrant spewing water.
After being forced to vault over a small ramp, straight ahead is a blue shipping container with an ammo box inside. To the right of the shipping container is the COG Tag.
During the final fight against the mortar teams, you will see a small driveway down a ramp into a garage. The COG Tag is on the left wall in the garage.
Underneath the mortar team is a small room with some frag grenades and the level's COG Tags.
During the section where you have to protect the bot from attackers, go to the back balcony on the upper floor. Facing out, the COG Tag is on the right side.
To the right of the exit, you will see a red COG spray on the wall. Follow the path to the right and you will find the collectible near an Onyx ammo case.
After killing everybody with the mech, look to the right of the exit door and up a small set of stairs you will see a blood smear on the ground leading to a door. To the left of the door is the collectible.
Hug the left wall from the start of the level and you will make your way up a small hill. Do a 180 and the collectible is on the ground.
Leave the garage at the very start of the level and you will see a small set of stairs on the left. At the top of the stairs is the COG Tag.
At the beginning of the level, you will drop down and see a ton of Locust swarming below. Stay up top and in the room to the right near the bottom of a small set of stairs is the collectible.
From the start of the level, go forward up a small set of stairs and turn right 180 degrees. Continue straight down a small hallway and the collectible is on the ground in the corner.
Walk forward until you see the DECLASSIFY challenge marker on the wall. The collectible is directly behind you.