You don't need to farm any item to complete the collection files, the way they work (at least for the older ones, havent checked out the newest ones yet) is that you complete a certain objective (complete expeditions, complete emergency quests, etc) and then you'll get points for completing them. So like if you clear a quest you'll get a 5% or 10% or whatever boost (think it increases based on difficulty/rank) and then once you get to 100% the next time you complete the specified objective, the specified item needed for the sheet will drop (will appear as a normal drop, but with a white/silverish color) and once you pick the item up it will be marked as "complete" on the sheet. Once you have all of the objectives completed, the sheet item will be deposited into your inventory automatically once all of the objectives are completed. Hope this helps!
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