//Lands

This deck has a curve so low that 2 mana in your starting hand is more than enough, and sometimes even 1 mana if you have a really cheap hand (your chances of having a 2 mana starting hand is around 75%). Anyways, if you dislike to play that risky you can change one Krenko for another land, but I woulnd't go further than 21 lands (way too many lands slow this deck too much).

Mountain: Since you are monocolor you can use as many mountains as you want. I use 10 since I don't want to risk losing efficiency by increasing the other lands numbers.

Prismatic vista: It reduces the chances you can draw another land, so it is good. Since you run 10 mountains, cards like path to exile won't bother you.

Shinka, the Bloodsoaked Keep: It behaves like a mountain. You'll rarely use the first strike ability, but it is better to have the chance to use it than not.

Sokenzan, Crucible of Defiance. Like Shinka, it is a mountain with a cool extra effect. Unfortunately the tokens aren't goblins, so they won't synergize well with the deck, but they are better than nothing.

Den of the Bugbear: Sometimes it comes into play tapped and you lose tempo due that drawback. Because of that I only use one copy despite not being legendary. This land is for lategame. If you are careless they will remove it, but if they can't the continuous creation of goblins will make the difference, specially versus control decks.

Cavern of Souls: The only real drawback of this card is to being unable to use goblin grenade with it. I could see a second copy (specially on blue based metas), but three are too many.

Fiery Islet and Sunbaked Canyon: Both cards serve the same goal. They are mountains that hurt your life points, but they give you the chance to cycle them and draw a better card for winning. If you like true risk you can use more copies of both cards (the faster the meta, the more risky to do this).

// Noncreature spells

Since goblin decks usually rely on creatures more than spells this section is quite small.

Goblin Grenade is your happy burst card. I use to finish people with it or sometimes I kill planeswalkers or big creatures. Trust me, the best use for your goblins is as grenades (specially the Scamp and the Mogg).

Shared Animosity is like a coat of arms but only for attack. Since you can create giant boards this card becomes a finisher on its own.

Dolmen Gate is card that I use for the sake of keeping my board alive.Whenever you face someone with very few creatures in their deck this should be the first card to sideboard since lacks usefullness.

// Creatures

Here it comes, the main section. You like goblins, you spam goblins, you kill enemies with a swarm of goblins (and some explosives). Let me introduce your main troops:

Legion Loyalist: Is the heart of your deck, you love him, you protect him (I still don't know how to do it propperly, but I use him less as a grenade than other goblins). This guy makes your goblins hard to kill giving them first strike. Because you get trample too, you don't waste your extra damage in little blockers, so you kill your foe faster and if he uses tokens he can't block with them (you'd be surprised of the amount of tokens that people creates even if their deck is not token based).

Goblin Bushwhacker: He makes your deck incredible fast and gives you some burst potential with his cheap aoe haste/stats boost. Once you've used his kicker he becomes just another spendable 1/1 goblin.

Cacophony Scamp: I know what are you going to say, the heck is this guy doing in a goblin deck instead of goblin guide (or at least a Mogg Fanatic). At the end of this huge text there is an explanation of why I don't use any of those cards. Here I'll explain why I do use this little goblin. At first this is a card that lacks of, well, everything. Standard one mana 1/1, when he dies deals 1 damage, except when someone changes his attack value (usually you, getting bigger numbers). I found this guy being surprinsingly amazing as a cheap blocker, a good sacrifice for the grenade or just an attacker. The 1 damage makes him extremely valuable since he can free kill a lot of creatures like the snapcaster mage, vendilion clique, esper sentinel, Ragavan, dark confidant, young pyromancer, grim lavamancer, etc, it also can slow down planeswalkers, finish off something damaged or just hit the opponent if there are not good targets. As a blocker he can kill 2 hit points bodies, making him more efficient than a Mogg Fanatic in defense (unless the Mogg can block and kill another attacking creature). The main drawback is that I can't force the damage, so the only ways to kill him is in combat or using the grenade (don't even try to mention the enemy using removals on him, it has happened to me only 1 time in four years, when I was using Goblin Arsonist instead). Proliferate is okay but you rarely will use it since only Krenko can get counters, and even then you will have to choose to sacrifice it and lose one attacker or bet that Krenko can safely pull an attack..

Warren instigator: This guy is a gambit, in early game he can win the game by itself if they don't remove him (only if you have the best goblins of your deck in hand, specially with sideboard done). If you draw him later he can do some heavy damage if you have some other goblins, specially the legion loyalist. If the warren is alone with no hand he's garbage for a 2 mana goblin. Because he is a bit risky to use I only use 2 copies, but the risk is worth.

Mogg War Marshal: He's my early game board creator. It also happens that he is good as a blocker, as grenade fodder and, if you give him haste, as an attacker. Don't forget that you must choose to echo or not on your next upkeep.

Goblin Wardriver: As long as you have some other goblins he becomes a threat (and a removal target). When he is alone, this guy is just a little better than the standard goblin.

Goblin Piledriver: If the loyalist is your beloved right hand goblin, this guy is your man for dirty jobs. He can put a lot of damage with very few goblins (and I mean a lot of damage), he can't be blocked by blue creatures (freaking snapcaster/subtlety flash) and also happens that he can't be targeted by the control abilities of Teferi, Hero of Dominaria or Jace, the Mind Sculptor. ¿Azorius control? Hah.

Goblin Chieftain: If this guys survives one or two turns the game is yours. Static aoe haste is the goblin wet dream, plus that stat boost he gives. You just can't complain about him, 3 copies (or 4 if you dislike using 2 Krenkos).

Battle Cry Goblin: Weird guy. Good stats, good abilities. He depends on being able to take advantage of his pack tactics and/or bushwackerlike active. I rarely play him on my first two turns since he works better latter.

Sensation Gorger: Your draw engine. Sometimes your goblins are wiped so many times that you need extra cards. With a 34 creature cards deck your chances of activating his ability are higher than 50%. When you summon him is quite common that your enemies have already used all his removals in hand. Other times he's just another goblin, so you use him as an attacker.

Krenko, Tin Street Kingpin: Every turn he survives the bigger is his menace. He gets bigger very easily and the stronger he is, the more globlins he summons. Strong guy. You may dislike using 2 copies due the legendary rule, so you may want to use another Goblin Chieftain instead.

//Sideboard

I use the sideaboard mainly for dealing with control decks, which make you unable to attack as you'd like. Lately artifact decks are bothersome too.

Goblin Chainwhirler: This guy is amazing, good stats, removes tokens, first strike. The only reason making him unable to be in the main deck is that the 3 mana cost is a very reduced group, because I can't force the mana curve more, and I can't even think of removing any card of it unless the right scenario is given. If you need to deal with another swarm deck or a deck which punishes swarm decks too much this card works better than Krenko.

Goblin King: Amazing versus red decks, not so amazing versus the other colors. Use him wisely and think what do you change for him (it depends a lot on what are you facing). He can combo with the blood moon, but don't try to force the interaction.

Blood Moon: Lovely card versus decks with a lot of nonbasic lands (almost every three/four color deck plus trons and hammertime), the slower is the deck, the stronger will be the effectivity of this card. the only bad part is that you can't use the prismatic vista search engine, and sometimes you miss the cavern of souls no counter policy.

Purphoros, God of the Forge: When someone controls you so hard that you can't even attack with your goblins, this card becomes a great option since it makes summoning goblins a true hell for your enemy.

Conspicuous Snoop: Similar to the Sensation Gorger, but cheaper. I like to run the Gorger since he gives me huge turns where I can burst the opponent and it can draw not goblin cards if you are lucky. Conscipuous is more stable longer term talking, but won't allow to use 2 goblin grenades by surprise. I still recommend him vs heavy removal based decks, since it allows you to cycle your deck faster. Remember, there is a small chance that if you are playing the snoop and Krenko, Mob Boss that you can use Krenko's active by surprise. He always replaces the Warren Instigator.

Krenko, Mob Boss: Warren Instigator best friend along the Goblin Chieftain. When everything fails, he manages to make you win (if he survives). Specially effective with purphoros.

Smash to Smithereens: Previously this decks used to be so good vs artifact decks that I didn't even need sideboard for them. Since hammertime became a thing, this has changed. This card becomes crucial when dealing with the deck. You may use abrade instead, but I rather deal 3 extra damage to them than be more capable of removing their creatures. If you expect a lot of people playing the deck consider getting more of this.

Goblin bombardment: When the opponent boardwipes this card allows to bombard the opponent with your goblins. Great vs control.

// Maybeboard

Tuktuk the Explorer: Tuktuk comes and leaves my sideboard constantly. He and Goblin Chainwhirler have a dispute for those two slots. Tuktuk works great on metas where creatures are decent sized (from 3 to 5 toughtness points). Haste allows him to get a fast Legion Loyalist trigger and his ability to create a 5/5 goblin (godlike stats for the race) by using the grenade makes him really good in certain scenarios. It works okay vs control since they can't boardwipe him easily.

Burn at the Stake: This is the big kaboom, the finish him of your deck. When the pure control deck happens to also heal so much that not even Purphoros can save you, this card makes you one turn kill almost everything. Burn those sticky bastards. On slow metas this card usually gets a chance to be on my sideboard.

Tarfire: You can go tarfire if you feel that another damage spell is needed. I rather use tarfire than lightning bolt due its sinergy with sensation gorger and conspicuous snoop.

Goblin Cratermaker: I haven't used this guy yet. If an eldrazi deck rises one day and is fast enough to compete with the goblin speed you can use him.

The Flame of Keld: High risk, high reward card. Since it is predictable I dislike it, but I won't deny its effectiveness if it is not properly responded.

Legion Warboss: I'd rather use Krenko, but this guy works okay too (is a bit faster due the instant goblin on precombat phase, but less destructive if let unchecked).

Squee, Dubious Monarch: I'd rather use Krenko, but in a meta where removals are too common I see him as an okay replacement.

Siege-Gang Commander: Fills a similar spot than Krenko, Mob Boss. Since he is expensive and less destructive than an unchecked Krenko I rather go the other option, but he definetly works.

Raid bombardment: Is a more stable option than the risky Shared Animosity, specially on metas where you won't be bothered by big bodies.

Moria Marauder: Not as consistent as it looks and cost 2 is quite crowded. It can replace Warren Instigator if you want better mid/late game rather than those random early drops, but I don't recommend trying to subtitute Sensation Gorger with him.

Connecting the Dots: Not a terrible alternative draw engine. Its main drawbacks are that if you have no goblins left it becomes useless and that you need to pay a second time the activated abilitie to get the cards. May be a good option vs high control decks.

More Blood Moon: Sometimes I think that a third moon or even a fourth would be amazing because they really break some decks. If you want to replace something from the sideboard for more moons I won't discourage you.

Other spells: If you search for other spells there are a few one that you may like. Forked Bolt works when the meta has weak creatures or spams a lot of 1 health tokens and lightning bolt is a good replacement for the grenade if you prefer the instant speed and/or dislike the summit of goblins (for those pacifist and "don't hurt the goblins" organizations).

// Why not play...

Goblin Guide: This is a personal reason. Goblin Guide gives you a lot of early game damage, most of the time managing to deal at least 4 damage. BUT, he can also make your enemy draw free lands (as a fast deck I dislike to give my opponent a chance to balance his mana curve, specially when he mulligans). Later he's a 2/2 haste with less chances of dealing damage but still the same chances of making your enemy to draw cards or at least know what card will draw (and information is power). Since the introduction of Ragavan, Nimble Pilferer this card is even worse, since most decks made their turn 1 responses more effective. The last reason I don't play this guy is because I can't find a place to put him in the 1 mana section. The loyalist makes the whole group too good, the bushwhacker gives me a lot of surprise element and burst potential and the scamp gives me control, expendable cards and a slight defense.

Mogg Fanatic: The battle between the scamp and this guys is almost tied. After some games I found the fireblade more effective for my playstyle, but the fanatic is also a great option that could work better versus some specific decks.

Goblin Rabblemaster: Sometimes you don't want to attack, even if you'd like to. Horrible vs midrange decks, but performs amazingly vs control decks. Unfortunately there are better options on the maybeboard. Only if the meta had next to zero creatures I'd give a chance to this guy since he hits like a truck.

Aether Vial: I put this into this section because some people has asked me along the tournaments. The vial is a card that I've seen in legacy goblins, mainly because they use those lands that tap other lands or the ones that sacrifice themselves and then destroy another land, so they can keep summoning via the Vial while they control the opponent mana. In modern ,Goblins can't work the same way.

Goblin matron: Amazing when you are looking for an specific goblin. Works better as sideboard vs control. Just can't fit her.

More Kings: Is not worth it, I can't see a way to fit four kings in the deck.

More Goblin Chainwhirler: More or less the same problem than the king.

Other Goblin stuff: I have tested a lot of goblins over the years (even a flying first strike goblin). Maybe the only worth mentions are the goblin banneret and Squee, the immortal. Anyways you can try a lot of combinations of goblins, maybe you find something I haven't seen in the past or a synergy with a new goblin (try Squee, the Immortal with Lightning Crafter, is super funny to see).

Mutavault: If you haven't noticed I play a risky deck that uses very few mana, so having a colorless mana that transforms into a killable 2/2 goblin is not worth it for me. In addition the Den is far more effective...