This is a more competitive EDH deck. I'd say it's on the upper end of casual but, it's not quite cEDH.
Your goal with this deck is to get Krenko out as fast as possible, preferably with protection in hand or on board like Lightning Greaves, Swiftfoot Boots, Deflecting Swat, or Goblin Chirurgeon. If you're playing against a blue opponent Pyroblast, Red Elemental Blast, Fork, or Reverberate will protect him against Counterspells.
How Do You Win?
You want to be able to use Krenko's tap ability as many times as possible to overwhelm the field with Goblin Tokens and swing in for lethal. The cards that allow you to untap Krenko or double his ability include: Magewright's Stone, Thornbite Staff, Patriar's Seal, Rings of Brighthearth, Staff of Domination, Thousand-Year Elixir, and Umbral Mantle. I considered Sword of the Paruns, but I decided it was too much mana to get that piece going.
Another way to win is to create a ton of Goblin Tokens while you have one or more of these out: Impact Tremors, Purphoros, God of the Forge, or Witty Roastmaster.
Ramp:
This deck runs a ton of "Fast Mana" because it aims to get Krenko out as fast as possible. Jeweled Lotus, Mana Crypt, Mox Opal, Mana Vault, Sol Ring, and Grim Monolith. Other mana rocks include: Arcane Signet, Fellwar Stone, and Thran Dynamo. You will notice that most of this "Ramp" is just artifacts that are efficient at producing only colorless mana. This is great, but the deck desperately needs red mana as well. So, the other "Ramp" pieces that help achieve this are Gauntlet of Might, Dockside Extortionist, Brightstone Ritual, and Jeska's Will.
Infinite Combo:
There's a few infinite combos is the deck, but they all need three pieces to become infinite.
Infinite Goblins/Infinite Colorless Mana/Infinite Draw: Krenko, Mob Boss + Mana Echoes + Staff of Domination
Infinite Goblins: Krenko, Mob Boss + Mana Echoes + Umbral Mantle
Infinite Goblins: Goblin Chirurgeon
+
Krenko, Mob Boss
+
Thornbite Staff
Infinite Gobling/Infinite Red Mana: Krenko, Mob Boss + Skirk Prospector + Thornbite Staff
Infinite Gobling/Infinite Colorless Mana: Ashnod's Altar + Krenko, Mob Boss + Thornbite Staff
Haste:
Because you won't always be so lucky to have the Impact Tremors type effect on the field, it is essential to give your creatures haste (Especially Krenko). The haste enablers include: Goblin Chieftain, Goblin Warchief, Ogre Battledriver, Urabrask the Hidden, Ashling's Prerogative (Krenko's CMC is even and your Goblin Tokens have CMC Zero, so they're also even), and Fervor. I chose to run Fervor over Hammer of Purphoros because being able to use the colorless mana from mana rocks for the same effect is more efficient. And no one in their right mind would ever us the Hammer's second ability.
It should also be noted that Lightning Greaves, Swiftfoot Boots, and Thousand-Year Elixir will allow you to tap Krenko the turn he comes out.
Lords:
Goblin Lords are a huge part of the deck and they help you make your 1/1 Goblins lethal.
Metallic Mimic, Adaptive Automaton, Goblin Chieftain, Goblin King, Goblin Warchief, and Goblin Trashmaster.
Insurance:
Goblin Bombardment and Boggart Shenanigans are good insurance for your investment in building your board. When a boardwipe hits (This will most likely happen) you will be able to sacrifice all of your creatures in response with Goblin Bombardment. And it should also be noted that Boggart Shenanigans counts as a Goblin for Krenko, Mob Boss's ability.
Massive Pump:
Shared Animosity, or Coat of Arms allow for massive beatdown. Be careful with Coat of Arms though. This is a "world effect" that also gives your opponent's creatures buffs as well. For example, your opponents may be running a commander like The Locust God (Another one of my favorite commander decks)
Unblockable Goblins
Goblin King + Blood Moon
Goblin King + Magus of the Moon
Notable Pieces
Torbran, Thane of Red Fell is broken in this deck. He adds 2 points of damage for everything you do (Combat and Non-Combat Damage)
A last ditch effort is Pandemonium. This is all or nothing. This should only be played if you have enough goblins on the field, AND you can tap Krenko to double your goblin count. if you have 20 goblins on field and then double them with Krenko, Pandemonium will only be able to do 1 damage 20 times, so this effects becomes much greater if you have Goblin Lords on the field. I recommend you only play this card if you are certain you can win the turn you play it.
Removal Spells Include: Lightning Bolt, Pyroblast, Red Elemental Blast, Chaos Warp, and Goblin Trashmaster.
Board Wipes Include: Starstorm, Blasphemous Act
Pieces to annoy your opponents: Blood Moon, Magus of the Moon, Vandalblast Ruination, and Price of Glory. These mainly annoy multicolored decks, but Price of Glory is there to dis-incentivize any shenanigans on your turn.
