The 8 foil cards are: Alolan Vulpix V Glaceon V Glaceon VMAX Pikachu Stantler Snom Glastrier Cryogonal Each one has a snowflake symbol on the middle-right of the card, around where other gift set stamps usually are - in the bottom-right corner of the artwork on a traditional Pokmon card
Like most Pokmon cards, the value of Skuntank V depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Silver Tempest)
Gardevoir decks have always been a popular choice in the meta in recent years, which adds to the allure of this card
Summon: LeviathanSummon: Leviathan, in particular, is extremely potent in such builds as it delivers a Whelming WaveWhelming Wave for its first chapter and then draws you a card whenever one of those creatures attacks (a trigger for each one, that is)
Verify weight, foil texture, and the exact gold/silver tone of the rarity stamp against a known authentic copy