I came across these two item names in the Shop Search:

They aren't in any shops or galleries or trades, and they aren't listed on SubetaLodge. The rarity number says they were Holiday Items. Is there any chance of me finding them for my balloon collection? ^X^;

there is a minesweeper-like game in Subeta, and the time it was introduced was the Ziara History plot that happened during Atebus Revolution Masquerade (2013). So either these items are game prizes, or still come from this game as an Achievement, or they only came as an Achievement for one of the steps of the plot so you won't be seeing them again unless someone who was here at the time sells them to you.

Awww okay. Thanks for the information! I've been playing the balloon sweeper game, so I'll try for the related Achievements, just in case!

I looked it up using the Account Search and found Item IDs of 161779 and 161780.

The items around those IDs include

[Item=iron lock picks]

which were from the 2013 Masquerade Plot. IIRC they disappeared after the step was completed similar to [Item=bucket of cool water]