Although the Japanese name of the "Mekk-Knight" archetype is only ジャックナイツ, its members' names are actually consist the words 機界騎士. Disregarding the kana, these words could be read as Kikai Kishi, literally "Mecha-World Knight", which could be a pun on the monster Type機械Kikai.
All "Mekk-Knight" Main Deck monsters (except "Mekk-Knight Avram", Normal Monster) share the following effect:
"If 2 or more cards are in the same column, you can Special Summon this card (from your hand) to that column."
Mekk-Knight Monsters rely on Special Summoning from the Hand and the Search effects like "Purple Nightfall" and "Blue Sky"; "Purple Nightfall" and "Indigo Eclipse" also have an effect to move a Monster out the way for another Special Summon being just as crucial to dump the Hand fast.
Most iterations of the deck also employ "Aleister the Invoker" (along with "Invocation", "Magical Meltdown", and the "Invoked" Fusion Monsters), not only to increase their offensive power but also to better safeguard their field presence (courtesy of "Invoked Mechaba"). This variant is commonly called Invoked Mekk-Knight. Other than that, this deck's core components (consisting of "Blue Sky", "Purple Nightfall", and "Indigo Eclipse", with a base count of 2, 3, and 1, respectively) can also be used in other decks that needs more swarming and offensive power.