Genex
Genex are a series of mostly Machine-Type monsters that have an affiliation with the various Attributes that exist in OCG, as hinted on the flavor text of "Genex Controller" and its trump cards, "Hydro Genex", "Thermal Genex", "Geo Genex", and "Wind Farm Genex". Most of their effects revolve around "Genex Controller", usually getting the aforementioned card in the hand or on the field for quick Synchro Summonings. The Genex Synchro Monsters have a variety of different effects, making them one of the more flexible Synchro-based Archetypes.
"Genex" monsters were introduced in "Duel Terminal - Invasion of Worms!", with further support added in "Justice Strikes Back!!" and "Champion of Chaos!!" (this support being in form of the Real Genex sub-Archetype).
Their names seem to be derived from several forms of energy development (Hydroeletric, Geothermal, Solar etc).
There is currently a Synchro Genex for every attribute except LIGHT
Genex monsters are also supported by a sub-Archetype known as Real Genex. Those cards focus heavily upon swarming to better enable Synchro Summoning.