Collected 100 attachments. *Does not include add-ons.Attachments are visual equipment items that will mostly be purchase from the Exchange portion of the shop. You can buy 35 of them from the normal portion of the shop with kin (the game's normal currency), and will get a small amount from quest rewards and pickups in the field, but the majority you'll need to exchange for. I'd suggest waiting until the end of your second playthrough when the entire Exchange shop is available (more items get added as you play through the stories), and then working on purchasing everything until the achievement unlocks. If you don't have enough materials for something, you can wishlist it and check the Enemies Library to find where those items drops, then return to a shop once you've collected everything.