Use this card in an "Earthbound Immortal" Deck, to discard 3 copies of "Earthbound Immortal", this way this card will have 9000 ATK, then use "Lightning Vortex" and attack for a possible OTK.
You can use "Monster Reborn" to Special Summon any "Earthbound Immortal" you send to the Graveyard through this card's effect (be sure to have a Field Spell on the field before doing so).
Another possibility is to use "Dark Hole" before you Special Summon "Montage Dragon", thus destroying any face-down monsters your opponent might have as well as the face-up ones.
This card is good in a high-Level Deck if you have Nomi-dead draws in your hand.
This card can also be used as an offensive power in typically passive-defensive "Gusto" Decks and at the same time sending "Gusto" monsters to the Graveyard instead of waiting for a "Gusto" monster to be destroyed (thus allowing many effects of "Gusto" monster to take place faster).
You can use "Summoner's Art" to get high Level monsters Normal Monsters (Eg. "Blue-Eyes White Dragon") to your hand, send them to Graveyard in-order to Summon this card and use "Birthright" to get the monster back.
By using "Backup Soldier" you won't lose that much hand advantage, being able to recover up to 3 Normal Monsters, for the ability to Summon "Montage Dragon".
This card works well with "Thunder Dragon" - discard one to get two of the pieces for "Montage Dragon". And this way, "Montage Dragon" will have a minimum of 3300 ATK.
Use this card to fill your Graveyard with high Level Dragons, and then use "Decoy Dragon" to Summon one of them. Cards like "Battle Mania" can force your opponent to attack.
When "Montage Dragon" is on the field, beware of cards such as "Book of Moon" that can switch your "Montage Dragon" into face-down Defense Position.
"Montage Dragon" is good in a "Sacred Beast" Deck especially if you have multiple copies and are unable to Summon them, as well as a "Gate Guardian" Deck, when you have no ability to Summon the pieces or the whole, it can easily have 7500 ATK.
If you run "Montage Dragon" in a Plant-Type Deck, you can send 3 copies of "Phoenixian Cluster Amaryllis" to the Graveyard, it will have 7200 ATK.
"Montage Dragon" works well with "Earthbound Immortals" and "Dark Armed Dragon", as you can send 2 "Earthbound Immortal" monsters and one other DARK card to the Graveyard, then Summon "Dark Armed Dragon" to potentially do 10000+ damage.
You can Synchro Summon "Black Rose Dragon" to the field and send it to the Graveyard to destroy all cards on the field and Special Summon "Montage Dragon" from your hand and attack your opponent directly for a high amount of damage.
Discard 3 monsters to Special Summon this card, then Tribute it for "Great Maju Garzett". Since the ATK of "Montage Dragon" is undetermined, the ATK gained from the discarded monsters is counted as its original ATK, meaning that "Great Maju Garzett" will be able to gain double its ATK for a maximum of 21,600.
This card can be a surprising trump card in a "Dragon Ruler" Deck. Simply discard three of the "Dragon Rulers" to Special Summon this card with a whopping 6300 ATK. Your Graveyard will now be set up for further "Dragon Ruler" plays.
It is possible to create an OTK by using "Sangan" in combination with "Limit Reverse". Recycle "Sangan" to get 3 Level 10 monsters, like "Yubel" into your hand. You can then discard all 3 copies of "Yubel" to Special Summon "Montage Dragon" with a combined attack of 9000.
A good card to send is "Red-Eyes Darkness Metal Dragon" since it's Level 10. It would make the ATK of "Montage Dragon" 9000, if along with other Level 10 monsters. If you use "Red-Eyes Wyvern" in your Deck, you can Special Summon them from the Graveyard later.
Use "Future Fusion" or "Painful Choice" to send 3 copies of "The White Stone of Legend" to the Graveyard, giving you 3 copies of "Blue-Eyes White Dragon" to your hand to discard for this card and give it 7200 ATK.
If your opponent decides to give you 1 copy of "The White Stone of Legend" to your hand for the effect of "Painful Choice", discard it by "Cards of Consonance" to draw 2 cards and still get your "Blue-Eyes White Dragon" to your Hand.
This card actually works quite well in a "Blue-EyesDisaster Dragon" Deck, as you will get a lot of hand advantage and high Level monsters as well as being able to discard "Red-Eyes Wyvern" and "Red-Eyes Darkness Metal Dragon" for another Summon, as long as you don't Normal Summon/Set, which you don't really need to do as it will have over 4200 ATK, or discard "White Stone of Legend" to search out "Blue-Eyes White Dragon".