Although Yuffie enters attacking when its ninjutsu ability resolves, it was never declared as an attacking creature (for purposes of abilities that trigger whenever a creature attacks, for example)
Elegant and always causing darkness to retreat, having one on your team might just give you a good sleep
Thus, FINAL FANTASY produces an interesting case as a Standard-legal Magic set - it's not powerful enough to where a ton of cards will have a huge impact, but at the same time it's refreshing to have a set introduced to the format that isn't full of cards that would drastically shake things up
Alternate Art Promos feature a collection of some of the most stylistically unique promo cards in the modern era, featuring Pokemon and trainers from XY, Unova, and more
Then they will fetch out a basic untapped, which is "may" effect but which will also trigger River Song on your foe if they do