"Proto-Cyber Dragon" can be used instead of "Cyber Dragon Core" if its ATK can be reduced to 500 or less. The effect of "Armored Cybern" can be used to achieve this, while destroying an opponent's monster.
Use this card while "Deskbot 001" is in your Graveyard and "Deskbot 001" can be Special Summoned as well, with a resulting attack of at least 2,500.
"Deskbot 001" is a Tuner, so a wide variety of Synchro Summons can be followed up. If your opponent is low on LP, "Armory Arm" can be good Synchro choice to inflict high damage.
Use this card on "Ancient Gear Box" to flood the field with Level 4 monsters. Then Xyz Summon.
The effect of "Box" is also useful for searching other monsters that "Machine Duplication" works with.
Before it was restricted, "Card Trooper" could be used, along with "Limiter Removal" or "Cybernetic Magician". Summon one "Card Trooper", then use "Machine Duplication" to get 2 more from your Deck. Then, if "Cybernetic Magician" is chosen, use its effect first to power them up, then use their effects to have 3 "Card Troopers" with 3500 ATK. If "Limiter Removal" is chosen,their effect can be used first, then use "Limiter Removal" to power them up to 3800 ATK each.
Using "Machine Duplication" with "Woodborg Inpachi" as a target will allow yourself to take up to another two from your Deck and Special Summon them in Defense Position. This will mean that there are three monsters with 2500 DEF. This is especially useful in a defensive Deck.
For an offensive strategy, "Woodborg Inpachi" could be Special Summoned in Attack Position. "Shield & Sword" can then be used to switch their ATK and DEF stats. Activate "Limiter Removal" to have 3 monsters with an attack of 5000.
"Delta Attacker" can also be used to allow the three "Woodborg Inpachis" to attack directly for an OTK.
Using "Alchemy Cycle" will reduce all your face-up monsters' ATK to 0 for the turn, allowing any Machine-Type monster to be usable for the effect of "Machine Duplication", include ones with high ATK or good effects.
Use "DNA Surgery" to allow more monsters to be used with this card.
In a "Frog" Deck, this combo can search almost any monster.
Using "Machine Duplication" on a LIGHT monster will provide at least 2 LIGHT monsters after its effect resolves, allowing yourself to Special Summon "Guardian of Order" from your hand.
Use "Power Converter" on a powerful Machine-Type monster to bring its ATK to 0, then use this card to Summon two more of that monster to the field (applicable only in Tag Force 4).
Use "Machine Duplication" on an "Ancient Gear" or "Ancient Gear Cannon" to provide the condition necessary to use "Spell Gear", granted there are 2 more in your Deck.
Equip any Machine-Type monster with "Darkworld Shackles" and it will be a viable target for this card. However, unless the original Machine is replaced, it will remain useless on the field and cost yourself LP by the other effect of "Darkworld Shackles".
Use a card such as "Hero Mask" to change the name of a Machine-Type monster with 500 or less ATK, then use this card to Special Summon 2 copies of whatever card the Machine-Type monster had its name changed to.
Main Deck Machine-Type monsters with 500 or less that can be Special Summoned: