Greiger's Decks

Season 1
Greiger used this deck for ground duels during the Fortune Cup.

Season 1
Greiger used this deck for Turbo Duels during the Fortune Cup.

When Greiger was transformed into a Dark Signer, he used this deck which consisted of his Reactors aswell as the Darksea series.

Season 2
Although Greiger wasn't seen dueling in season 2, he was shown losing to Jack Atlas.

Manga
In the manga, Greiger plays a Fusion-based Deck, with cards allowing quick and repeated fusion summons like "Charge Fusion" and "Extra Fusion". His Fusion Monsters, like "Ignition Beast Volcannon" and "Blaze Fenix, the Burning Bombardment Bird", inflict effect damage.

Video games
In all the games, Greiger Deck are considered unusable because most of them use 3 Dark Strike Fighters, which are forbidden. Even with the ban lifted you can only use one and no more than that.

In Duel Transer you can duel him on Bifrost 6th Floor only if you have Earthbound Immortal Chacu Challuha. To beat him means to unlock his Deck recipe, which you can't use in the game because this Deck uses three Dark Strike Fighter cards.