Narcosis

There are 19 ID cards to collect throughout the game, the last one given automatically after the credits have finished rolling. Apart from that one, these are all taken from corpses of your dead colleagues, and most are in pretty plain sight. You will see a glowing blue light where there are cards to collect, so look out for them. A couple are a bit out of the way, but a little exploring should see you get them all. If you pause the game and go into “Event Log” and go to the chapter you are on, you can see how many collectables there are per level. The game will autosave once you have collected anything, so you can use chapter select to mop up, exiting out of the level once you have what you need.