Higure, the Still Wind [Planechase 2012] Grand Prix Promos Scholars say that arbiters exist

Scholars say that arbiters exist on every world

Set: Avacyn Restored Type: Creature — Angel Rarity: Rare Cost: {1}{W}{W}{W} Flying

Set: Unlimited Edition Type: Land — Forest Plains Rarity: Rare ({T}: Add {G} or {W}

Set: Guilds of Ravnica Prerelease Promos Type: Creature — Spider Rarity: Rare Cost: {5}{G}{G} Reach

Unfortunately

Higure, the Still Wind [Planechase 2012] Grand Prix Promos Scholars say that arbiters existSet: Planechase 2012 Type: Legendary Creature Human Ninja Rarity: Rare Cost: {3}{U}{U} Ninjutsu {2}{U}{U} ({2}{U}{U}, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand tapped and attacking.) Whenever Higure, the Still Wind deals combat damage to a player, you may search your library for a Ninja card, reveal it, and put it into your hand. If you do, shuffle your library. {2}: Target Ninja creature can't