Because there hasn't been a full list of costume headgears listed on the wiki or anywhere for that matter, I decided to make my own list for not only my own reference but for others as well. I'll try my best to update this list as often as I can when new things come out. Feel free to comment below if there is any costume I might have missed.
All Costumes released from alora's box are able to be gotten by refining the item obtained in game to +8 even after the box stops granting those hats. (This is not true for hats not obtainable in game normally) Alora's Box is also Tradable, however when exchanged the costume becomes account bound.
Event Costumes are not obtainable in game after event whatsoever unless re-released or Traded/Bought from another player. (If costume is tradable, if not normal event headgears usually can still be +8'd to obtain it from "Alora"? Point in case = Polar Bear Hat)
All Kafra Shop Costumes are perma obtainable from kafra shop unless stated otherwise. (Like a costume being removed) These costumes come in a box and the box is tradable/vendable, however when opened the costume becomes account bound.
The Preview Section has been added (Character Simulation List), Clicking the "Wearable" button takes you to a character simulator that previews the headgear so you can see what it looks like on a character. Unfortunately, the list is incomplete as not all the hats are listed in this particular simulator. Any preview not found will be marked with a "N/A".
Minor Update Notes: Last Updated Tuesday, February 4th 2014
Currently Working on Eclage Costumes~
(If you have any info about missing information here, feel free to contact me :3 )
As of the 10/2/13 Maintenance , a good chunk (if not all, still need to test them) costumes are now tradable. The list will be updated to reflect that change.
Buy Costume: Butterfly Ears Box from Kafra Shop for 150 Kafra pts (Box is tradable, costume is account bound)
Costume: Bolt Ears
Buy Costume: Bolt Ears Box from Kafra Shop for 150 Kafra pts (Box is tradable, costume is account bound)
Character Simulator List (WIP)
The Character Simulator List is of the current costumes shown in a character simulator. (This list has been changed to the "Preview" section, any costume available in the simulator is marked with a "Wearable" button, there are still hats missing so the missing ones are marked with a N/A)
Costumes Available in kRO Currently..
The following links show the costumes avaliable in other versions of RO
More Info will be added as it is obtained. If you notice anything incorrect, or have suggestions on a change that could be made to assist this compendium, you can leave me a message here in the comments. Thank you.