The "rarest" thing in my FFV swag stash is this complete trading card collection from Bandai I think? They did promotional crossovers with all kinds of popular games/movies/anime/manga, and trading cards were only available in packs of 4 from official vending machines, typically for the span of a year or so around the target media's release date. They'd even set up official events where you could meet and trade.

Not sure who did this artwork for all the items and equipment, as it doesn't match any of the other offical artist styles. I have them all in one of my other guides, but these are the biggest versions of them I've seen.