The "Swamp [Foil]" card from the Magic: The Gathering Invasion set is classified as an Unknown rarity, holding the collector's card number 341. Currently valued at $2.84, this foil land card is sought after for its aesthetic appeal and functional role in various deck strategies. As a key component of the game’s mana base, it remains a staple in many black-themed decks and is of interest to both players and collectors alike.