Item Collections is a new set of achievements with new, unique rewards that are tied very specifically to the finding of items and skins. In the new Collections section of the Achievements panel, you will find a handful of new achievements.
— Official website
- Most collections are hidden and will only appear in the achievements panel once an item from that collection has been consumed or account-bound.
- The categories themselves are also hidden until at least one of their collections has been unlocked.
- Any item that is part of a collection will have it noted in its description, so long as the collection is unlocked.
- The Collections achievements were added in the September 2014 Feature Pack.