Since the English version of Volume 58 - the third volume of XY - just came out yesterday, I figured it was a good time to share my notes about which Vivillon patterns are featured on the cover! There are 15 patterns featured, which match up with the patterns used by the Sky Trainers in this encounter in-story.
(Bulbapedia claims that Jungle Pattern Vivillon appears in this battle while Marine Pattern Vivillon debuts later, but I’ve looked at all the panels with Vivillon in them and I don’t see Jungle Pattern anywhere, while Marine Pattern’s clearly present.)
Some interesting things to note:
Yvette’s Elegant Pattern Vivillon is the pattern found in most areas of Japan.
Notably absent is the Meadow Pattern Vivillon, which is the “default” pattern depicted in Vivillon’s official art – it’s the pattern that can be found in France.
Also notably absent are the event-exclusive Fancy and Poké Ball patterns, which the story makes a point to say that Yvette owns.
The other two absent patterns are the Ocean Pattern and the Jungle Pattern, which are found primarily in Hawaii and parts of Central/South America, respectively.
If you start from the Polar Pattern Vivillon and make your way clockwise around the Vivillon circle, the patterns appear in the exact same order that they’re listed on Serebii, with the only patterns out of order being the Elegant and Icy Snow Patterns.