Three "Blue-Eyes White Dragons".
In Yu-Gi-Oh! 5D's World Championship 2009: Stardust Accelerator, Yu-Gi-Oh! 5D's World Championship 2010: Reverse of Arcadia and Yu-Gi-Oh! 5D's World Championship 2011: Over the Nexus, Helio as well as Stephanie uses a Deck revolving around "Blue-Eyes White Dragon".
Blue-Eyes-oriented decks generally involve Summoning "Blue-Eyes White Dragon" through various support cards. One of which is to use "Dragonic Tactics" which allows a Level 8 Dragon-Type monster like "Blue-Eyes White Dragon" to be Special Summoned from the Deck by Tributing two Dragon Type monsters. Another is to Ritual Summon "Paladin of White Dragon" with "White Dragon Ritual", using "Manju of the Ten Thousand Hands" to search out either "White Dragon Ritual" or "Paladin of White Dragon". Other strategies revolve around cards such as "Kaibaman", "Kaiser Sea Horse", "Dragon's Rebirth", "Eclipse Wyvern", and "Ancient Rules". It also fits well in Dragon Lords Decks, as it can be Summoned with "Decoy Dragon" or discarded for "Trade-In" and "Montage Dragon". It also has a Tuner support monster, "The White Stone of Legend", which can be used in tandem with "Cards of Consonance".
"Totem Dragon" is a very useful way to Summon high Level Dragon-Type monsters. It can be sent to the Graveyard from the hand or Deck with various cards such as "Vanguard of the Dragon" or "Darkflare Dragon", and can also be used as a Synchro Material Monster along with the Tuner "Debris Dragon" for a Level 6 Dragon-Type Synchro Monster, or use with "Bright Star Dragon" for Xyz Summoning "Queen Dragun Djinn", which can revive more "Blue-Eyes White Dragons" from your Graveyard. Totem Dragon is also counted as 2 Tributes for Tribute Summoning Dragon-type monster, so it can also be used together with another powerful Level 8 Dragon, "Light and Darkness Dragon". With high ATK, powerful effect negation (albeit hard to control), and revival effect upon its destruction, it can serve as alternatives for controlling the field until you can delivering finishing blows. Due to it being Level 8, it is compatible with "Trade-In", and can also be used for Xyz Summoning "Hieratic Sun Dragon Overlord of Heliopolis" if the situation calls for it.
Its Fusion Monster, "Blue-Eyes Ultimate Dragon", is involved in One Turn Kill scenario. "Blue-Eyes Ultimate Dragon" is often Fusion Summoned through a combination of "Future Fusion" and "Dragon's Mirror" (or "Cyber-Stein" in the Traditional Format). Combined with "Megamorph" and Spell & Trap-clearing cards so that it can launch a direct attack to win. However "Five-Headed Dragon" is often a better choice for "Future Fusion" and "Dragon's Mirror" (as is "Cyber Twin Dragon" for the "Cyber-Stein" strategy). A strategy for this card is to Fusion Summon "Blue-Eyes Ultimate Dragon" and then use "De-Fusion" to Summon all three copies of "Blue-Eyes White Dragon" to the field (and maybe use "Delta Attacker" if your opponent has monsters on their side of the field). Alternatively, you can Tribute "Blue-Eyes Ultimate Dragon" to Summon "Blue-Eyes Shining Dragon" which has the benefit of not being targeted by card effects, and gains 300 ATK for each Dragon in the Graveyard. Once it is Summoned, it automatically has 4200 ATK and is easily boosted to somewhere around 5000 if you have a strong Dragon-based deck.
Aside from the mentioned cards, other monsters that can be included are more Dragons for "Dragon's Mirror" to Fusion Summon "Five-Headed Dragon". "Luster Dragon" and "Alexandrite Dragon" can serve as both attackers and Tribute Fodder for "Advanced Ritual Art", also for Xyz Summoning options when paired with "Hieratic Dragon of Gebeb". "Elemental HERO Prisma" can also be used if utilizing "Blue-Eyes Ultimate Dragon" by sending "Blue-Eyes White Dragon" to the Graveyard via its effect so that they can later be used with "Dragon's Mirror", or just for instantly activate "Burst Stream of Destruction". "Red-Eyes Darkness Metal Dragon" can be used to Special Summon "Blue-Eyes White Dragon" and other high-powered Dragons from the Graveyard. Another strategy involves either "Lord of D." and "The Flute of Summoning Dragon", or "King Dragun". Because relying on "The Flute of Summoning Dragon" generally results in a massive loss of card advantage, "King Dragun" is generally preferred. "The Light - Hex-Sealed Fusion" can also be used as a Fusion Substitute if utilizing "Blue-Eyes Ultimate Dragon" or "The Dark - Hex-Sealed Fusion" can be used if utilizing "King Dragun". "King of the Swamp" is a third option, particularly because you can discard it to fetch "Polymerization", and can also acts as Fusion Substitute for both "Blue-Eyes Ultimate Dragon" and "King Dragun" for "Dragon's Mirror".
The Deck may also utilize Normal Monster and LIGHT support cards such as "Birthright" and "Freed the Brave Wanderer". "Honest" can also be included for supporting LIGHT Attribute monsters such as the previously mentioned "Elemental HERO Prisma". "Champion's Vigilance" is a great Counter Trap because it can negate any Spell/Trap or monster Summoning (much like "Solemn Judgment") if you control Level 7 or higher Normal Monster (such as "Blue-Eyes White Dragon"). "Non-Spellcasting Area" can also be used to bypass the attack-canceling effect of "Burst Stream of Destruction". "Return from the Different Dimension" and "Dimension Fusion" (Traditional Format) are also useful for Summoning large amounts of monsters banished due to "Dragon's Mirror", to attack directly and win the game. You can also use 3 "Blue-Eyes White Dragon", "Treaty on Uniform Nomenclature" and "Delta Attacker", to pop your opponent Spells and Traps and then have all 3 "Blue-Eyes White Dragon" attack directly even if your opponent has monsters on the field.
"Azure-Eyes Silver Dragon" is a Synchro Monster that requires 1 Tuner + 1 or more non-Tuner Normal Monsters to summon. When it is Special Summoned, Dragon-Type monsters you control cannot be targeted or destroyed by card effects until the end of the next turn. Additional, during your Standby Phase you can Special Summon 1 Normal Monster (e.g. "Blue-Eyes White Dragon") from your Graveyard. This card is the reason why "Maiden with Eyes of Blue" is a Tuner support monster, like "The White Stone of Legend".
"Thunder End Dragon" is an Xyz Monster that requires 2 Level 8 Normal Monsters to summon. While on the field, you can detach one of its overlay units to destroy all other monsters on the field, clearing your way for a finishing blow. Because of the play style of Blue-Eyes cards, you can get out "Thunder End Dragon" easily enough to do this, and if possible, you can also use "Hieratic Sun Dragon Overlord of Heliopolis" to destroy any remaining cards that cannot be destroyed by the effect of "Thunder End Dragon".
The "Hieratic" archetype also merges very well with this Deck.