Engine

An "engine" is a card combinition that works good together, but contains to few cards to make a full deck. If an engine focuses on raising consistency, it is called a Draw Engine. Here are some examples of popular engines:

The Tour Guide Engine
Uses Tour Guide From the Underworld to summon level 3 fiends to quickly Xyz summon rank 3 monsters such as Leviair the Sea Dragon,Wind-Up Zenmaines and Number 30: Acid Golem of Destruction. It originally consisted of 3 Tour Guides and 1 sangan. After Tour Guide was Semi-Limited due to the engines popularity, it began using other level 3 fiends, most often Night Assailant, But sometimes Dark Mimic LV3 or Tour Bus From the Underworld.WATER decks can use Cloudian - Poison Cloud.

The Plant Engine
Consists of Glow-Up Bulb, Spore, Lonefire Blossom, Dandylion, Debris Dragon and One for One. Allows for fast synchro summoning. Was rendered unplayable in march 2012 with the banning of Spore and Glow-up Bulb, But is now somewhat playable with the return of spore aswell as the semi-limiting of Debris Dragon.