Chapter 1: Museum of Military Glory
COG TAG 1: OLD TOWN
Just before you enter the museum, turn to the right and enter the small park. Across from you, you will see the Blood Omen on the wall and the tag will be on the ground just to the right of it.
COG TAG 2: RIVERWALK DISTRICT
After you reach the turret in the courtyard area, go up and around the stairs and down the stairs on the far. To the right will be an alley way with the Blood Omen on the far wall. Look to the right on the ground to find the tags.
COG TAG 3: MUSEUM GARDENS
As soon as you break down the door to enter the Museum Gardens, go to the right and follow the alley way there all the way around to the end to find the COGs on the ground.
COG TAG 4: GREAT HALL
When you are setting up for the wave assault, go down to the main floor and enter the fountain in the center of the room. The tag will be in the water to the front of the statue.
COG TAG 5: KASHKUR WING
Once the battle starts. Make your way to the far center of the ground floor and the tag will be on the ground in front of a pillar there.
COG TAG 6: EAST WING
When you are waiting for the assault to begin to protect the armor, go to the hallway on the right hand side and there will be a body with the COG tag in there.
COG TAG 7: ARCHIVES
After you destroy the Serapede eggs and go through the large metal door, you will enter a warehouse with tall shelving. Go to the left side about halfway through the warehouse and you will come to a body to the right, down a short alley. You can grab the COG tag from there.
COG TAG 8: VAULTS
When you enter the vault, after the first wave of enemies, a second will come from the right side of the room near the far end, to the right of a set of stairs. Once the Locusts are dead there, go to the area on the right where they came in and you will find the COG tag on the ground next to the large hole in the ground.