By Cerberus.Kuching 2012-08-09 06:34:22
Copied from a guide I wrote:
"These can be obtained in many different ways. From NPC vendors, dropped off trolls, crafted with Goldsmithing and Alchemy, dropped off the ZNM Ob, ISNMs, ENMs, Chocobo digging, Ground of Valor chests or in exchange for Imperial standing. All attachments can be bought and sold through the Auction House or Bazaars. Most attachments should be bought from NPCs or from the AH. If you have time, you can try the Hilltroll Puppetmasters and Ob for a few uncommon ones. The expensive/best ones should be farmed from the battlefield they come from if you really truely cannot afford the AH price.
You should try and obtain all of the attachments anyway, but some are less useful then others."