There are 242 collectibles to find in Murdered: Soul Suspect. There is 9 sets of artifacts, and 8 sets of artifacts for all the ghost stories. You will earn pretty much the entire trophy / achievement list from collecting all 242 of them. One thing you need to keep in mind, some of the locations are missable! The museum for example, is a one time visit. When you reach the judgement house, don’t go in it until you have all the collectibles.