Way back when this thing received its official distribution to Japanese 3DSes, I posted an announcement and routinely scanned the comments for people to add: http://gtm.steamproxy.vip/groups/GCCX#announcements/detail/1155409557073286958

Since Steam always sends you notifications when people reply to a discussion, I reckon a discussion thread will be easier to keep track of. Just copy and post with the template provided below. Once your requests are fulfilled, edit your post accordingly.

My friend code is 0946-2283-6120.

Other things to mention:

 ● You cannot receive any stationery until you unlock the feature yourself.
  ● It's unlocked by creating and saving (but not necessarily sending) 5 notes.

 ● As well as the official GCCX stationery, I can also send you anything listed here:
  https://picasaweb.google.com/107604352268990282594/SwapnoteLetterboxSendableStationeryTheEntireCollection

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Friend Code: 0000-0000-0000
Mii Name: Asdf123
Has GGCX Stationery?: Yes/No
Looking for other stationery?: Yes (+ examples) / No