Jumpstart: Historic Horizons contains hundreds of cards from Modern Horizons, Modern Horizons 2, and more — including 32 new-to-Magic cards in this MTG Arena-only release. Similar to the original Jumpstart release on MTG Arena, you select from themed boosters to build a deck for play. There are 46 different half decks. Jumpstart: Historic Horizons introduces a new dynamic to packet picking and deckbuilding: select card slots in each packet have a chance to be filled with alternate cards that fit the theme.