Pearl Medallion (Foil Etched) [Commander Masters]

Pearl Medallion (Foil Etched) [Commander Masters]Set: Commander Masters Type: Artifact Rarity: Rare Cost: {2} White spells you cast cost 1 less to cast.

or Ebon Praetor

Beneath crashing waves lies an ocean of secrets waiting to be explored

Set: International Collectors' Edition Type: Sorcery Rarity: Uncommon Cost: {1}{G} Return target card from your graveyard to your hand

Set: Battle for Zendikar Promos Type: Creature — Eldrazi Rarity: Mythic Cost: {9} Your opponents can't cast spells with even mana values

Pass me from soul to soul / soldier to herder

For a more complicated concept

the players will cultivate land plots

Whenever a Mountain enters the battlefield under your control

you don't lose the game for having 0 or less life

Set: Judge Gift Cards 2017 Type: Sorcery Rarity: Rare Cost: {3}{U}{U} Take an extra turn after this one

no more than one creature can attack you each combat

It's an essential resource for Dungeon Masters to use in populating any type of challenge they might contrive for their players