More info, specifically some of the cards, has been noted on the official product page.
Release Date: October 18th, 2018
Coming this holiday season, the Yu-Gi-Oh! TRADING CARD GAME Advent Calendar returns to honour an old-time tradition of counting down the days to Christmas, in a way fi t for a Duelist!
The Yu-Gi-Oh! TRADING CARD GAME Advent Calendar contains 24 doors, full of holiday themed cards to add to your collection and power up your Decks. Box of Friends, Toy Magician and many more cards can be found to get Duelists into the holiday mood!
Each Yu-Gi-Oh! TRADING CARD GAME Advent Calendar contains:
• 14 Super Rare Cards and 10 Ultra Rare Cards