Even with all of the changes and return-t0-the-roots nature of Call of Duty WW2, somethings will never change like trying to find all of the collectibles in the singleplayer campaign. The roughly six hours-long story is comprised of 11 total missions spread across the entirety of World War II.
Within every mission, there's are three glowing collectible "mementos" to find that vary from a knife to a canteen. Not only are these memento collectibles important to completionists, but they will be important to achievement and trophy hunters as well.
The mementos in Call of Duty WW2 are tied directly into the achievement/trophy "Pieces of History" that tasks you with finding all 33 of them that spread across the 11 missions of the campaign. Here are the locations of all memento collectibles in Call of Duty WW2's first half of the campaign. You can find the rest of them here.
Call of Duty WW2 Memento Locations: D-Day
During the Ascend the Bluffs objective, your squad will go up the beach. Before following them, go to the end of the trench to the bunker there. This first memento knife is in the open section of the bunker facing the beach as seen above.
When you are tasked with clearing out the fourth bunker with your squad, you will need to go back through the large trench around the courtyard to a newly opened bunker there. Inside of it is the memento compass.
Before you destroy the artillery with the charge, go to the abandoned barn to the left and you will find this rather small memento located on a shelf right next to the entrance.
Call of Duty WW2 Memento Locations: Operation Cobra
Before you get onto the tank at the start, go to the group of barrels to the right of the area and find the lighter on top of one of the barrels there.
After exiting the woods, you will be tasked with clearing out the soldiers around the AA gun and mounting it. Before you mount the gun, go to the back of these farmlands to find a little empty shack. The glowing pocket watch is located in there on a table.
When you are tasked with getting behind the tanks to advance through the battlefield, stop and go down the trench on the right. In a corner, you will find this dead soldier wearing the gas mask.
Call of Duty WW2 Memento Locations: Stronghold
At the beginning of this mission, you will have take a church. Access the second floor of the church by using the rightmost stairs to go up. There will be a section of the wall that has been blown apart. Go to it and look left to find a mirror above a sink with the locket attached to it as seen in the picture above.
Wait until you have finished clearing the church out before you grab this one. Go to the right side and to the back of the church. There is a small portion of the floor that is blown out in this area. Within the small crater, there is an almost too perfect square where the pin is located.
Right before the Germans begin the counterattack and you must defend the area, quickly go down the stairs on the right to a pile of rubble. You will find the cannister there and you must grab it before the Germans get too close.
Call of Duty WW2 Memento Locations: S.O.E.
This is a pretty challenging one due to it being a stealth mission. This pamphlet is located outside the house you follow Crowley into and is found in a bucket near a few soldiers. Quickly and silently take them out without alerting the other soldiers or you will have to restart.
At the point where you enter a house to rendezvous with Vivian and Crowley, you will have to execute a guard in the house. Go to the left of where the guard was and you will find a piano that has the collar on top of it.
This is located in the area where you are attacked by a dog right before you jump over the log to rendezvous with your squad. Go to the back corner of this area and you will find these laid-out plans atop a group of crates.
Call of Duty WW2 Memento Locations: Liberation
You will be tasked in this mission with going to the basement to find Fischer. On your way down to the basement, you will have to walk through the ladies' restroom. This pamphlet is lying on the floor in the first bathroom stall on your right.
Before you start the stealth portion of this mission, you have to find this rather challenging memento. Begin by going around the ledge on the side of the building you are in that will take you above the north gate. Go up the roof and drop down to the other side. You will find the bottle in the hidden room on your right.
Upon destroying the half-track right before the end of this mission, don't rally with your squad just yet. The medal is lying on a group of crates covered with a tarp near the Resistance fighters that are celebrating your victory.
Call of Duty WW2 Memento Locations: Collateral Damage
A machine gunner will begin firing on your squad during this mission. In the alley where he is located, there is a piano on the left side of the street. On top of the piano is the sheet music memento.
After clearing out the apartment, you must reach the second apartment by going to the collapsed ceiling and going up the broken parts of the ceiling to the second floor. Go to the entrance of the apartment to find a large hole in the floor in this apartment. The cigar box is on the other side of the hole atop the fireplace. You must navigate around the large hole to the other side.
When you enter the hotel, don't go upstairs just yet. It is located easily in the open compartment underneath the front desk of the hotel.