There is a whole bunch of classes Poetica outfit boxes not showing on the central market.

However when you search for the mystic outfit is shows in the drop down, but when you click it it says "No results found". What's even more odd is the armor piece of mystic is shown in the above image but no set.

This happens when the outfit was never listed on the central market yet. The search can only show items that were listed in the marketplace at least once. So while you can search it in the dropdown menu, where all items are included, the marketplace doesn't yet result in anything