The following cards will be banned in their respective tournament formats, taking effect on October 25:
Standard format. Field of the Dead is banned.
Pauper format. Arcum's Astrolabe is banned.
Field of the Dead was banned for terribly obvious reasons. It was the engine for one of the most metagame-defining decks in recent history, "Golos Ramp", which represented 42% of the field at Mythic Championship V, and warped the competitive field so badly that the metagame was boiled down to "Golos decks vs. Decks Built To Beat Golos Decks". Arcum's Astrolabe was also banned in the Pauper format after a few months of helping multicolor Skred decks achieve a win rate greater than 55%.Wizards of the Coast also announced a brand new tournament format for Magic: The Gathering called Pioneer that will be supported on the Pro level. This format includes all Standard-legal cards from Return to Ravnica and beyond, except for the five fetch lands that would be legal: Bloodstained Mire, Flooded Strand, Polluted Delta, Windswept Heath, and Wooded Foothills. This is essentially a "rotated-forward Modern format" in an attempt to include more recent players who don't have immediate access to the more expensive Modern cards.
The ban of Field of the Dead and the addition of the Pioneer format is great news for retailers. The Standard format has been opened up again, now that the oppressive Golos Ramp decks have been powered-down a bit, and this should lead to more sales of Mythic rare and rare cards from recent sets as players build out more Standard-legal decks. The Pioneer format is a massive boon to retailers. It opens up a whole swath of new decks for competitive players to create which will likely also result in an increase in singles sales. Many of cards printed from sets printed in the last five years have had extremely depressed prices, and Frontier will finally give some these cards a chance to move out of store binders for decent prices.
Magic: The Gathering last banned cards on August 26, ending the Summer of Hogaak (see "Wizards of the Coast Updates 'Magic: The Gathering' Banned and Restricted Lists ").
Click on Gallery below to see the full-size infographic for the Pioneer format!