WHAT IS PIONEER?
Pioneer—a new nonrotating format featuring cards from Return to Ravnica and forward
Pioneer is a constructed format and therefore adheres to the following constructed rules:
Minimum of sixty cards
No maximum deck size, as long as you can shuffle your deck unassisted
Up to fifteen cards in your sideboard, if used
With the exception of basic lands (Plains, Island, Swamp, Mountain, Forest, and Wastes), your combined deck and sideboard may not contain more than four of any individual card, counted by its English card title equivalent.
All Standard releases from Return to Ravnica forward are legal
The following card sets are permitted in Pioneer
Throne of EldraineCore Set 2020War of the SparkRavnica AllegianceGuilds of RavnicaCore Set 2019DominariaRivals of IxalanIxalanHour of DevastationAmonkhetAether RevoltKaladeshEldritch MoonShadows over Innistrad
Oath of the GatewatchBattle for ZendikarMagic OriginsDragons of TarkirFate ReforgedKhans of TarkirMagic 2015Journey into NyxBorn of the GodsTherosMagic 2014Dragon’s MazeGatecrashReturn to Ravnica