"Goblin" (Japanese: ゴブリン Goburin) is an archetype based on "Goblin Attack Force" and "Goblin of Greed", and their variations. The theme didn't have any support until The New Challengers, in which "Scrounging Goblin" was released.
Most members share the effect "If this card attacks, it is changed to Defense Position at the end of the Battle Phase, and its battle position cannot be changed until the End Phase of your next turn." (though not necessarily with the same wording) and also share 0 DEF. However, most of the cards in this archetype have very little synergy with each other, being relased over different periods of the game advancing in rules.
"Goblin of Greed": Carrying an effect that benefits the original draw and discard power of "Goblins", this card can also be used to counter "Mermail", "Fabled", "Knightmare", "Infernity" Decks, and as well as cards like "Snipe Hunter", and the searching effects of "Nekroz" monsters. This card prevents the activation of "Lightning Vortex", "Cards of Consonance", "Trade-In", "Divine Wrath", "Twin Twister" and many other powerful cards.
"Scrounging Goblin": Being the main search engine in the Deck, this card can search and add any other member of the archetype to your hand. Use an effect that switches ATK and DEF to make easier to this card inflict battle damage to your opponent , then you can search "Robbin' Goblin" and "Hard-Sellin' Goblin" to increase your card advantage. Set this card in face-down defense position. If this card is attacked by opponent's monster with 1900 or less ATK, you can get this card search effect. "Battle Mania" is useful another useful card to combo with this one and gain more advantage, if you have incresed this card's ATK or DEF by a good amount with another card.
"Goblin Attack Force": One of the more powerful attacking monsters in the Deck, activate "Final Attack Orders" to have this card switch back to Attack position after its effect resolves, or "Skill Drain" to remove this downside effect altogether. This effect to change this card to Defense Position is shared by all the other monster in this archetype with "Goblin" & "Squad" in their name, and "Goblin Black Ops". You can return this card from your Graveyard to your Hand with "The Warrior Returning Alive"
"Goblin Elite Attack Force": With similar stats equal to that of the original "Goblin Attack Force", this card can make up more of your offensive monsters. However, using "Mist Body" to prevent this card from being destroyed in battle while in Defense Position, so that it can replenish its offensive poise later to attack once again.
"Goblin Black Ops": Despite being one of the weaker offensive "Goblin" cards. it's effect to attack directly can end up winning a duel unexpectedly, or allowing you to combo some of your active "Goblin" Continuous Traps. This card can also be returned to your hand with "Recurring Nightmare", or also added to your hand via "Fire Formation - Tenki".
"Goblin Recon Squad": While this card's effect isn't often counted on to get rid of your opponent Spell cards, it's mainly used to see your opponent's hand. However, using this card in combination with "Respect Play" or "Fengsheng Mirror" to know what your opponent has, thus allowing you can guarentee destroying all of your opponent's Spells. You can return this card from your Graveyard to your Hand with "The Warrior Returning Alive".
"Goblin Marauding Squad": With a similar effect to that of "Deskbot 009" & "Armades, Keeper of Boundaries" and good ATK for a Level 4 Monster, this card can guarentee that your Battle Phase will be safe, allowing you to easily gain card advantage via "Robbin' Goblin" & "Hard-sellin' Goblin". This card can also be returned to your hand with Recurring Nightmare", or also added to your hand via "Fire Formation - Tenki".
"Goblin Decoy Squad": Even though this may be one of the weaker "Goblin" cards, it has useful draw engine in it's effect, and has wide variety of other uses. You can attack directly with this card by using "Secret Pass to the Treasures" and activate its effect more easily. This card works well with "Guard Penalty", which will make you draw 2 cards. Use this card together with "Labyrinth of Nightmare" in a Clown Control Deck. The Clowns will clear the field, and thus will allow this card to attack every turn. You can return this card from your Graveyard to your Hand with "The Warrior Returning Alive" and "Recurring Nightmare".
"Goblin Pothole Squad": While this card disables your opponent's Trap cards upon being summoned, it also shuts down any "Trap Hole (archetype)" cards, thus making this card can very useful in shutting down the "Traptrix" archetype. You can return this card from your Graveyard to your Hand with "The Warrior Returning Alive".
"Toon Goblin Attack Force": Simply just different variation of the original "Goblin Attack Force" but with the inherent Toon effect, preventing it on attacking the turn it's summoned. You can return this card from your Graveyard to your Hand with "The Warrior Returning Alive".
"Blindly Loyal Goblin": Having an effect the makes sure it will always stay under your control, use this card in combination with "Mystic Box" to freely destroy an opponent's monster and keep this card on your side of the field. You can return this card from your Graveyard to your Hand with "The Warrior Returning Alive".
"Coach Goblin": This card is used in a different variation of a "Goblin" Deck, focused on Xyz & Link Summoning. It can be useful for returning the 2nd copy of a certain Normal Monster to the Deck, where it (along with the 3rd copy) can be Special Summoned by the effect of "Rescue Rabbit", allowing for quick summoning of monsters from the Extra Deck, as well as giving you more draw power.
"Goblindbergh": Being able to Special Summon any other of your "Goblin" monsters from hand, this card is very useful for Synchro Summoning (if you add in any Tuner Monsters) as well as Xyz and Link Summoning. Summon a Tuner with this card's effect for a quick Synchro Summon, or Summon a Level 4 monster and overlay them for a Rank 4 Xyz Monster. Special Summon "Sacred Crane" to draw 1 card and then Xyz Summon for a Rank 4 Xyz Monster. Special Summon a monster that shifts to Defense Position after attacking, like "Goblin Attack Force". After the Summon, activate "Final Attack Orders", so both monsters do not switch to Defense Position. You are now able to attack with two monsters, then Xyz Summon for a Rank 4 Xyz Monster. You can return this card from your Graveyard to your Hand with "The Warrior Returning Alive".
"Goblin King": Used as the main card in a more Beat-Down variation of a "Goblin" Deck, your entire strategy would focus around this card, since it gains 1000 ATK for each Fiend monster on the field while also being protected from attacks while you control another Fiend monster. Equip with "Opti-Camouflage Armor" for great amounts of Direct Damage. If you use "DNA Surgery" and choose Fiend, "Goblin King" increases its attack points by 1000 from virtually every monster on the field, and also makes your other "Goblin" monsters much more viable in this variation of the Deck. Summon 2 "Goblin Kings" from the Graveyard with "Puppet Master" to create an instant lock. "Goblin King" equipped with "Raregold Armor" with other Fiends on the field creates an instant attack lock. Whereas "Zerozelock" to protect this monster when you have no other Fiend monsters on the field. You can return this card from your Graveyard to your Hand with "Recurring Nightmare".
"Goblin Calligrapher": A simple Normal monster in the "Goblin" archetype, this card can be useful in the more Xyz & Link focused version of the Deck, in combination with cards like "Rescue Rabbit" and "Coach Goblin".
"Knightmare Goblin": Even though originally part of the "Knightmare" archetype, this card can be extremely useful in a "Goblin" Deck; being easily summonable via "Goblindbergh", allowing for draw power of co-linked whilst protecting your other Link monsters, and an extra Normal Summon per turn, allowing to swarm the field with more of your "Goblin" monsters, or an Xyz Summon with "Rescue Rabbit".
"Goblin Thief": One of the first "Goblin" Spell cards released, it allows for either quick Effect Damage to finish a Duel, and easy Life Point gain. Useful in a Burn Damage variation of a "Goblin" Deck, this is a good card to be used while "Fire Princess" is face-up, inflicting 1000 points of damage and increasing yours by 500. Combine those cards with "Dark Room of Nightmare" and "Spell Absorption" and you will inflict 2400 points of damage and increase your Life Points by 1000.
"Upstart Goblin": One of the most viable and easiest draw power cards in the game, it's run at 3 copies in any "Goblin" Deck. This card can be combined with "Bad Reaction to Simochi", "Darklord Nurse Reficule" or "Asleep at the Switch".
"Peeking Goblin": This card is useful to make your opponent draw a card that is a Dead Draw. It's also useful to somewhat predict your opponent's strategy, and return to the bottom of your opponent's Deck a card that he/she would need to draw. This card works well against "Infernity" decks: Use this card to return "Infernity Archfiend" to the bottom of the deck, so your opponent cannot draw it and cannot Special Summon it, nor can search an "Infernity" card.
"Robbin' Goblin": This will be one of the main card you search out with "Scrounging Goblin", and you'll be utilizing it with most of your "Goblin" cards, and directly with "Goblin King" and "Goblin Black Ops". Out of all the 'hand destruction' cards available, this can be one of the most efficient. The majority of other hand destruction cards are one-use-only, but this can allow you deplete an opponent's options every time you inflict battle damage. During a prolonged duel where you've inflicted minor or major damage to the opponent multiple times, they will be hard-pressed to have any useful cards remaining in their hand for long. This card, when comboed with "Hard-sellin' Goblin" while your opponent has no cards in his hand will create a combo that will destroy a Spell or Trap each time you inflict battle damage.
"Hard-sellin' Goblin": As said before with it's good combination with "Robbin' Goblin", you can also se cards like "Heavy Slump", "Bubble Crash" or "Goe Goe the Gallant Ninja" in conjunction with this card. your opponent's hand will be overflowing and they will have to get rid of many of their cards.
"Goblin Out of the Frying Pan": While at first not seeming like a useful Counter Trap, this card can actually be useful in negating your opponent's Spell and Trap cards that can only be activated once per turn. Plus, it can also be used in combos similar to that with "Hard-sellin' Goblin", with cards like "Heavy Slump" & "Bubble Crash".
"Good Goblin Housekeeping": Your main source of draw power in a "Goblin" Deck, search this card quickly with "Scrounging Goblin" or send two copies from the Deck to the Graveyard with cards like "Foolish Burial Goods", to allow faster draws with the third copy, allowing you to draw 3 cards. Once activated, it is best to send this card to the Graveyard before it resolves, so that it can count itself for an additional drawn card. Once all 3 copies of this card have been used, "Mask of Darkness" can be used to retrieve a copy and abuse its effect. "Trap of Darkness" can also combo well with this card, but only with more copies of this card in the Graveyard. Multiple copies of "Trap of Darkness" become less effective with this card, since this card is banished when that Trap Card resolves.
"Goblins" have an enormous advantage in ATK. Because of this advantage, "Goblins" may be the strongest Level 4 monsters. However, though the "Goblins" have several advantages in their original ATK, they have a drawback that makes a Deck containing them somewhat hard to use. This drawback is that after most "Goblin" monsters battle, they must change into face-up Defense Position. So, this Deck will be tricky to use in tournament play. To prevent this drawback, you can add copies of "Final Attack Orders". They will help you optimize the "Goblin's" strength. You can also use "Skill Drain" to prevent this effect while negating your opponent's card effects at the same time. You can also use "Zero Gravity" when most of your strong "Goblins" are in defense to switch them to attack, or for an added bonus use "Gamushara". ("Zero Gravity" switches all monsters from their previous positions ex. defense to attack or attack to defense). These cards would also work well in a "Spider" Deck and "Clown Control" Deck.