Wizardry: Labyrinth of Lost Souls

Because of the insane amount of farming you have to do in this game, this should come naturally for most people. If you still don't have it after getting all of the other trophies (except for the 200 hour one), you should take a look at the Spreadsheet in the roadmap or at this list I found.

You can also check your progress in the Album at the Inn. You don't need to carry every single item with you at the same time, you just have to carry it at some point in the game so that it gets saved to the Album. Unfortunately it won't tell you how many items you have exactly but you can either count them or just take note that there is a total of 140 items without DLC, so you will have reached 100 items at around 70% completion.

If you're having major problems with this one and want to purchase DLC, then go for the additional scenario (the one for 7,99$) since there are some more items to get within the new dungeon.

The trophy will unlock after getting your 100th item.