Hmm... I thought it might be Make It Rain items from last year (did we get anything? I don't actually remember...) but apparently that's June 6, we're still 2 weeks away.

I suppose it could be some of the items that were datamined ages ago. Probably the aforementioned carpet. Maybe even the Far Eastern Schoolgirl/boy outfit? It's been in game files forever, localised strings and all. It would make sense to finally release it while we're still in Stormblood.