31. Human Finger Necklace

This one will probably require multiple tries as you have to run like hell to get to it, and it's hard to explain where it is until you realize that you should be running like hell, and by then it's probably too late. As you move forward, Dom will mention something about a beacon, you'll get a new objective and you'll hit a checkpoint. Once the checkpoint hits, you'll enter a large room. Immediately start running up the small set of stairs to your left, and then hang right and run up the stairs, towards the closing gate. Dive under the gate if you need to. Once through the gate, make a right and the collectible is on the floor. You're now in a good position to light up the next roomful of Locust with the handy nearby Troika, so yay for you.

Chapter 4 - No Turning Back

32. Locust Calendar

Once you disembark the cable car, find the spiral staircase and go up it. At the top of the stairs, look to your left and you'll see something resembling a sun dial. This is the collectible.

33. Locust Defense Plans

The game will force you to split up, however once you're back together, hit the switch to extend the bridge. Cross the bridge and go left. The collectible is next to the ammo box.

Chapter 5 - The Best-Laid Plans

34. Locust Invasion Map

You'll get to a point where the only way into the Locust stronghold is by riding a lift. Position yourself with your back to the lift and you'll see some stairs with cage like doors on them. Go through the doors and you'll come to another set of cage doors. The collectible is on the stairs in front of the doors.

35. Trinity Of Worms Artifact

You'll have to split up again, so be sure to take the upper path. You'll go up some stairs and then down some stairs and then come to a second set of stairs leading down. Look around for an ammo box at the bottom of the stairs. The collectible is next to the ammo box.

Chapter 6 - Royal Inquisition

36. Locust Tablets

Once Cole is done bloviating, turn left and head towards the wall. The collectible is past the last column on your left.

Act 5 - Aftermath - 5 Collectibles

Chapter 2 - Desperate Stand

37. COG Recon Report

When on the south platform (the first platform that you have to defend) search out the balcony that's farthest away from your starting point. You'll come to an ammo box next to a set of stairs leading down. Go down the stairs to get the collectible.

38. COG Tag CSID: 911706-DZUHO-JN

After you defend the Comm-Sat, the Colonel will open a gate for you. Go down the passage and look to your left for a set of stairs heading down next to a fellow COG soldier. The collectible is at the bottom of the stairs next to the ammo box.

Chapter 3 - Free Parking

39. Jacinto Sentinel Newspaper

You'll come to an area where you and Dom will need to turn a gear to lift a gate. Do so and then go into the courtyard. Once the courtyard has been cleaned out, head to the right from your starting point and look for the chain link fence. Take a right at the fence and walk until you see a car and a red barrier. Look on the ground for some leaves. That's where the collectible is.

Chapter 4 - Tenuous Footing

40. COG Tag CSID: 444526-MI2K9-3B

Once back together with Dom, go out the hole in the building. Do a 180 and you'll see another hole, next to the one you just exited. Enter this hole and the collectible is on the floor.