Murktide Regent [Secret Lair Showdown] Clamfolk Set: Classic Sixth Edition Type:

Set: Classic Sixth Edition Type: Artifact Rarity: Rare Cost: {2} Whenever a land enters the battlefield

Set: Kaladesh Prerelease Promos Type: Artifact Rarity: Rare Cost: {3} Whenever you cast an instant or sorcery spell

Set: Commander 2011 Type: Legendary Creature — Elf Rogue Rarity: Rare Cost: {1}{G}{U} Whenever a creature deals combat damage to one of your opponents

then Set boosters are the way to go

Murktide Regent [Secret Lair Showdown] Clamfolk Set: Classic Sixth Edition Type:Set: Secret Lair Showdown Type: Creature Dragon Rarity: Mythic Cost: {5}{U}{U} Delve (Each card you exile from your graveyard while casting this spell pays for {1}.) Flying Murktide Regent enters the battlefield with a +1 +1 counter on it for each instant and sorcery card exiled with it. Whenever an instant or sorcery card leaves your graveyard, put a +1 +1 counter on Murktide Regent.