You can find it in this Yu-Gi-Oh! card set:
- Labyrinth of Nightmare
- Limited Edition Pack 6
- Structure Deck 10: Machine Re-volt
- Hobby League Participation Card: Series 5 and 7
- Crossroad of Chaos
- Raging Battle
- Duelist Pack: Yugi
- Machina Mayhem
Yugi Mutou (not Yami Yugi) is the one who shows using these cards when facing Yami Yugi.
Gadgets are a mildly well known set, due to their effects and appearance in the Yu-Gi-Oh! Anime series. Players often use them to get ahead in what is considered card advantage, by gaining another Gadget in hand each time a gadget is summoned and protecting the Gadgets with numerous removal and negation-based cards like Sakuretsu Armor and Royal Oppression. The card known as Elemental Hero - Stratos (E. Hero Airman) tended to neutralize the use of Gadgets this way. Stratos has recently been restricted in play, allowing Gadget use to thrive again.
When players reference "Gadget Monsters" they are typically referring to the monsters listed above, but technically "Gadget Soldier," "Gadget Arms," "Gadget Hauler" and "Gadget Driver" are treated as a "Gadget" monsters since they also have "Gadget" in their names, and as such they can be used with the "Gadget" support card, "Boot-Up Soldier - Dread Dynamo". However, "Gadget Soldier" has no distinguishing advantages beyond this and the other three are intended purely as support for "Morphtronics" monsters.
Since their release, Gadgets have also become support cards to the "Ancient Gear" monsters (actually the Gadjiltron Archetype), due to "Ancient Gear Gadjiltron Chimera" and "Ancient Gear Gadjiltron Dragon," which require Tribute Summoning by tributing Gadgets of particular colors to gain certain effects. As Gadgets are all EARTH-Machines, like Ancient Gears, as well as the fact that Ancient Gears need ready access to Tribute Fodder, the two archetypes merge well.
Main Article: Archfiend; Yu-Gi-Oh! Archetype Cards
