"A-to-Z-Dragon Buster Cannon".
Currently, the only cards that support this series are the "Heavy Mech" Union Monsters, "Frontline Base", "Union Hangar", "Roll Out!", "Formation Union", and "Union Scramble". Also, the Japanese lore of "Hyper Coat" specifies Machine-Type monsters with "Ｖ", "Ｗ", "Ｘ", "Ｙ", and/or "Ｚ" in their Japanese names. The members of this series are the card's only valid targets, so for all intents and purposes they are an archetype.
|A-to-Z||Dragon Buster Cannon|
|VWXYZ||Dragon Catapult Cannon|
"Ancient Fairy Dragon" can be used to Special Summon the pieces if they are in your hand, and "Summoner Monk," "Shining Angel", or "Jade Knight" can be used to search out three of the specific monsters necessary for assembling the more powerful Fusion Monsters. Also, since all of the Archetype's key monsters are LIGHT attribute, "Saffira, Queen of Dragons" can be used to recycle them back to your hand or for extra draw power. By using the effects of "XYZ-Dragon Cannon", "ABC-Dragon Buster", and "A-to-Z-Dragon Buster Cannon" to constantly discard LIGHT monsters, "Saffira" will be able to constantly recycle one of them back to your hand during the End Phase of each turn, or draw more cards, making for a powerful and much needed draw engine in "A-to-Z" Decks, by allowing you to draw 2 cards during the End Phase of each and every turn.
Basic Union Monster support Spell Cards are useful, such as "Frontline Base" and "Roll Out!". If you choose to include such cards, "Heavy Mech Support Platform" and "Heavy Mech Support Armor" provide more targets, and are useful when equipped to the fusion monsters, as it protects them from being targeted or destroyed by your opponent's cards. You can also equip the fusions with "A-Assault Core", "B-Buster Drake", and "C-Crush Wyvern", summoned to the field at once via "Union Scramble", and you will have a powerful monster that cannot be targeted by (if it is equipped with "Heavy Mech Support Armor") and is unaffected by all your opponent's Spells, Traps, and monster effects (if equipped with all three "ABC" union monsters). If they are all equipped to "A-to-Z-Dragon Buster Cannon", it is likely to keep a lot of pressure on your opponent during a duel since "A-to-Z" is a 4k beatstick that they will not be able to target with the likes of "Castel, the Skyblaster Musketeer" or "Dark Rebellion Xyz Dragon", nor have their spells, traps, or effect monsters' abilities work against it, that also has the ability to negate anything they attempt as long as its user has cards they are willing to discard.
LIGHT-support spells in general also work, particularly "Honest", seeing as it is both handy to protect the individual Union and Normal Monsters in addition to being a spectacularly effective way of paving a way to victory for the bigger Fusion Monsters, especially "A-to-Z-Dragon Buster Cannon". A particularly devastating strategy is swarming the field with the base monsters, then using "Limiter Removal" to give them a huge rise in power just to finish the turn with fusing them together. "Dimension Explosion" can act as a sort of "De-Fusion" for these cards, only the targets to return to the field or Extra Deck are not limited to Fusion Monster-Fusion material relation. "Lightwave Tuning", "Torque Tune Gear", and "Chaos-End Master" are useful for any Synchro Summons.
The "A-to-Z" cards are all about Unions. They are able to "combine" into the ultimate fighting machines, "VWXYZ-Dragon Catapult Cannon", "ABC-Dragon Buster", and "A-to-Z-Dragon Buster Cannon"; all powerful forces, they are able to banish monsters, change battle positions, and even constantly negate the opponent's card effects in a manner similar to "Herald of Creation" in the case of "A-to-Z-Dragon Buster Cannon", making "Saffira, Queen of Dragons" a viable option for decks that include the ABC monsters and especially their respective Fusion Monsters.
While "VWXYZ-Dragon Catapult Cannon" is powerful on your turn, it has no self protection, so adding cards to protect it would be wise, like "Ultimate Providence". You can also use "Premature Return", "D.D.R. - Different Dimension Reincarnation" or "Magnet Reverse" to re-summon this card. "Dimension Explosion" can help, especially when you can use it to help bring back monsters used for "XY-Dragon Cannon", "YZ-Tank Dragon", or "XZ-Tank Cannon" as alternatives to be able to Summon "XYZ-Dragon Cannon". As three of the base cards are Union Monsters, Union support such as "Frontline Base", "Union Hangar", "Union Scramble" and "Roll Out!" are viable options. "Morphtronic Scopen" is an ideal Tuner monster to use, as it can be Special Summoned through "Machine Assembly Line", "Machina Armored Unit" and "Shining Angel" and can function as a Tuner of both Levels 3 and 4.
Although "VWXYZ" has the ability to banish 1 card, the effect of "XYZ-Dragon Cannon" can be used multiple times in a single turn. Therefore, by removing "V-Tiger Jet" and "W-Wing Catapult" from your Deck and relying solely on "XYZ-Dragon Cannon" and "ABC-Dragon Buster", you are left with more room to fill your Deck with other useful cards. By using a similar method to the one explained above you can create a Deck that can Special Summon "XYZ" and has Fusion Monsters that aren't so tough to get on to the field. The ABC Union monsters and "Heavy Mech Support Armor" can be used to protect your Fusion Monsters, "Power Tool", or "Cyber Dragon" monsters from the negative effect of "Limiter Removal" without needing to worry about sacrificing Equip Spell Cards being used with "Power Tool Dragon".
Using cards like "Reckless Greed" (carefully) to draw cards to use as 'ammo' for the effect of "XYZ-Dragon Cannon" is an effective way to clear the opponent's field. It is also good to play an "Overload Fusion" and "Cyber Dragon" for a "Chimeratech Overdragon" to put out enough ATK to finish you opponent off, or as a back-up plan if your "A-to-Z" monsters are destroyed. By the time you have an "XYZ-Dragon Cannon" on the field and used its effect to destroy your opponent's cards you should have enough monsters in your Graveyard to use "Overload Fusion". Also, remember adding a few Synchro Monsters like "Karakuri Shogun mdl 00 "Burei"" and "Power Tool Dragon" (equipped with Double Tool C&D) to keep the opponent occupied until you can Summon an "XYZ-Dragon Cannon".
"D.D.R. - Different Dimension Reincarnation", "Premature Return" and "Magnet Reverse" can also be used to re-summon your banished "XYZ-Dragon Cannon" or "ABC-Dragon Buster" that was used to summon this archetype's strongest monster ("A-to-Z-Dragon Buster Cannon"), the latter being able to revive "ABC-Dragon Buster" from the Graveyard as well.