Tarot sets that include two or more decks instead of just one.
The Golden Dawn Enochian Skrying Tarot is an innovative, non-traditional Tarot of 89 cards that contains two decks in one - the Enochian Watchtower Tarot and the Western Tattvas Tarot. The cards are intended for skrying, divination, and magickal work.
The Sunrise/Sunset Tarot is a dual set of two majors-only tarot decks, created by Italian artist Giovanni Monti. The two 22-card decks are only sold together, and can be used together or separately.
The Complete Tarot Kit has copies of two incredibly influential tarot decks - the Rider-Waite Tarot and the Thoth Tarot. Accompanying the deck is the book, Introduction to Tarot, by Susan Levitt. The book has full-colour comparative pictures of both decks and is a basic intro to using tarot.
The Word of One Tarot is a set of 123 cards from three different decks - each deck designed to represent a different state of consciousness. There is a reprint of the 79-card T: The New Tarot for the Aquarian age, a 22 card Medieval-style deck, and a 22 card black and white deck representing the Atlantean Age. The cards have a heavy, sticky laminate and adhere together very easily. The publishers are currently looking for a buyer for the deck, including all the inventory and copyrights.