At the beginning of each opponent's end step, Keeper of the Accord checks for how many creatures and land cards the opponent controls
Many cards have Shift or abilities that rely on certain types and numbers of characters being in play (we're looking at you, Seven Dwarfs)

Here's a list of my favorite cycling cards for under $2: Scarab Feast, Aura Extraction, Censor, Clear, Miscalculation, Rapid Decay, Wipe Clean, Complicate, Expunge, Forsake the Worldly, Radiant's Judgment, Rescind, Resounding Wave, Spell Snip, Swat, Unburden, Akroma's Vengeance, Cast Out, Lay Claim, Decree of Silence Disruption: Jhessian Zombies, Noble Templar, Sanctum Plowbeast, Shoreline Ranger, Eternal Dragon, Ancient Excavation, Gleam of Resistance, Migratory Route Landcyclers: Barren Moor, Blasted Landscape, Drifting Meadow, Lonely Sandbar, Polluted Mire, Remote Isle, Secluded Steppe Lands: Angelsong, Gilded Light, Akroma's Blessing, Rune of Protection: Black (the entire cycle) Protection: Wander in Death Recursion: Cloud of Faeries, Esper Sojourners, Vizier of Tumbling Sands, Scion of Darkness Untap: Curator of Mysteries, Horror of the Broken Lands, Dirge of Dread, Decree of Justice Other: Cycling Zur ($53) Here's a sample list to give you an idea on how all the pieces can fit together: Whenever I build a deck, I start with a base ratio of 50 mana sources (lands + ramp), 6 spot removal, 3 board wipes, 10 sources of card advantage (mostly card draw), 2 recursion, 1 graveyard removal, and 2 flexible tutors

Key features: Official Magic: The Gathering product