Buster Flare - Insane levels of ATK

[Lunar Origins]

 

Cannot be used as an Xyz Material.  When a "Buster Flare" monster you control is returned to the hand, except "Buster Flare Dhampir":  You can Special Summon this card (from the hand).  All "Buster Flare" monsters you control gain 200 ATK.  If you control 5 "Buster Flare" monsters:  You can Tribute this card and 3 other "Buster Flare" monsters to target 1 "Buster Flare" monster you control;  That target gains 10000 ATK.

 

 

Cannot be used as an Xyz Material.  When a "Buster Flare" monster you control is returned to the hand, except "Buster Flare Rex":  You can Special Summon this card (from your hand).  You can Special Summon this card (from your hand).  If you do:  Return this card you control to the hand.  You can only activate this effect of "Buster Flare Rex" once per turn.

 

 

Cannot be used as an Xyz Material.  You can discard 1 "Buster Flare" monster;  Special Summon this card (from your Graveyard).  If you control another "Buster Flare" monster:  This monster's Level becomes 8, and its ATK is doubled.  If this card you control is sent to the Graveyard:  Target 1 "Buster Flare" monster on the field;  Return that target to the hand, then you can Special Summon any number of "Buster Flare" monsters from your hand, except the monster returned by this card's effect.

 

 

Cannot be used as an Xyz Material.  You can return 1 monster you control to the hand;  Special Summon this card (from your hand), and if you do:  You can Normal Summon 1 "Buster Flare" monster from your hand without Tributes in addition to your Normal Summon or Set.  When this card is sent from the field to the Graveyard:  You can target 1 card on your side of the field;  Return that target to your hand, then you can Special Summon 1 "Buster Flare" monster from your Deck in face-up Defense position.

 

 

4 "Buster Flare" monsters

Cannot be used as an Xyz Material.  During either player's turn, if a card effect is activated:  You can return this card to your hand instead of your Extra Deck and reveal it.  During the End Phase of the turn this card was returned to the hand this way:  Special Summon this card.  Once per turn:  You can target 1 "Buster Flare" monster you control;  Double that target's ATK, but all Battle Damage inflicted by that monster to your opponent becomes halved (this effect is permanent as long as that monster remains on the field).

 

 

Fusion Summon 1 FIRE Dragon-type Fusion Monster from your Extra Deck, by banishing monsters from your hand, field, or Graveyard as Fusion Materials.  When this card is sent to the Graveyard:  Target 1 card on the field;  Destroy it.

[Yemachu]

[spoiler="Buster Flare Dhampir"]

Cannot be used as an Xyz Material.  When a "Buster Flare" monster you control is returned to the hand, except "Buster Flare Dhampir":  You can Special Summon this card (from the hand).  All "Buster Flare" monsters you control gain 200 ATK.  If you control 5 "Buster Flare" monsters:  You can Tribute this card and 3 other "Buster Flare" monsters to target 1 "Buster Flare" monster you control;  That target gains 10000 ATK.

Although this card's effect can increase the targeted monser's ATK by a enormous amount, I feel like its cost is extremely high; losing 4 monsters to have a monster you control gain 10,000 ATK. However the increase is permanent (the way it is worded now), and some monsters in the archtype can double (and later maybe quadruple) their ATK. This might balance out the cost, but it is a quite risky effect (opponent finishes with a card like "Magic Cylinder" or "Dimension Wall").
 
Since my main concerns with this card are its high costs, I don't think it is really overpowered. Therefore it might not even need tweaking (not all cards need to be on the edge of being banned/limited/semi-limited).
[/spoiler][spoiler="Buster Flare Rex"]

Cannot be used as an Xyz Material.  When a "Buster Flare" monster you control is returned to the hand, except "Buster Flare Rex":  You can Special Summon this card (from your hand).  You can Special Summon this card (from your hand).  If you do:  Return this card you control to the hand.  You can only activate this effect of "Buster Flare Rex" once per turn.

The line "You can Special Summon this card (from your hand)" looks a bit weird, as it is stated twice in a row. I do understand that the second one triggers its returning effect, which helps the archtype. But it looks like some sort of typo.  
 
That is about all I have to say about this card; its stats seem to be a bit low, but the other cards can strengthen it. There is an issue with its effect, but I will deal with that later in this post.
[/spoiler][spoiler="Buster Flare Skai"]

Cannot be used as an Xyz Material.  You can discard 1 "Buster Flare" monster;  Special Summon this card (from your Graveyard).  If you control another "Buster Flare" monster:  This monster's Level becomes 8, and its ATK is doubled.  If this card you control is sent to the Graveyard:  Target 1 "Buster Flare" monster on the field;  Return that target to the hand, then you can Special Summon any number of "Buster Flare" monsters from your hand, except the monster returned by this card's effect.

You are aware of the fact this card's effect can backfire quite easily? If this card is sent to the Graveyard, either as a Fusion/Synchro Material, a tribute or it is destroyed; you must return 1 "Buster Flare" monster you control. If you are holding no "Buster Flare" monsters, but do control a "Buster Flare" monster (maybe even empowerd by "Buster Flare Dhampir"), you are forced to return that card to your hand. You can make this effect optional, or keep it as the risk of running this card.
 
Not being able to bes used as an Xyz Material, makes this card's level changing effect a bit redundant. Uses I can think of are running it with "The Calculator" (as most "Buster Flare" monsters are high leveled) or use it for a high leveled Synchro Monster.
[/spoiler][spoiler="Buster Flare Agu"]

Cannot be used as an Xyz Material.  You can return 1 monster you control to the hand;  Special Summon this card (from your hand), and if you do:  You can Normal Summon 1 "Buster Flare" monster from your hand without Tributes in addition to your Normal Summon or Set.  When this card is sent from the field to the Graveyard:  You can target 1 card on your side of the field;  Return that target to your hand, then you can Special Summon 1 "Buster Flare" monster from your Deck in face-up Defense position.

The way this card's effect is worded, does not allow your other "Buster Flare" monsters to activate their effects; they will miss their timing (another monster is Special Summoned). I do not know if this was intended, I guess so, since the card grammer you use is quite accurate. If that was not your intention, you should replace the underlined "then" with "and". That way the effects activate at the same moment, allowing to chain to either effect.
 
As for the (ab)usability, this card can aid in quickly summoning Level 8 monsters; which you cannot use for an Xyz Summon. I guess it supposed to help "Buster Flare Dhampir", otherwise I cannot think of much uses for its effect other than powering up the aformention "The Calculator".
[/spoiler][spoiler="Buster Flare Finaldrake"]

4 "Buster Flare" monsters
Cannot be used as an Xyz Material.  During either player's turn, if a card effect is activated:  You can return this card to your hand instead of your Extra Deck and reveal it.  During the End Phase of the turn this card was returned to the hand this way:  Special Summon this card.  Once per turn:  You can target 1 "Buster Flare" monster you control;  Double that target's ATK, but all Battle Damage inflicted by that monster to your opponent becomes halved (this effect is permanent as long as that monster remains on the field).

Returning a Fusion Monster to the hand: that is an effect I have not seen before. The returning effect can be used to evade dangerous cards, but what happens when you cannot Special Summon it during the End Phase (no usable Monster Card Zones, "Summon Limit", it has not been Fusion Summoned)? Is it sent to the Graveyard, does it stay in your hand until it is discarded, can you Normal Summon it by tributing monsters you control? Also for how long should I reveal this card, only when it is returned, or for as long as I am holding it (a bit like "Golden Ladybug")? Quite a lot of quircks to a seemingly simple effect.
 
My suggestion to fix this card effect is something along the lines of: "During either player's turn, if a card effect is activated: You can banish this face-up card, this is treated as this card being returned to the hand. During the End Phase of the turn this effect was activated: return it to the field in face-up Attack Position. "
 
Boss monsters tend to be powerful, but a 6000 ATK (actually 3000 but I used its effect on itself) beatstick which gets exponentially stronger each turn seems overpowered ("Limiter Removal" is limited for a reason). Instead of halving the inflicted Battle Damage, you can reduce it to a set amount (let's say the monster's Level x100). That way it can still deal damage, but has no real usage for its tremendous ATK. For the permanent part of the effect, I think you meant to word it like the effect of "Gravity Blaster". 
[/spoiler][spoiler="Buster Fusion Evolution"]

Fusion Summon 1 FIRE Dragon-type Fusion Monster from your Extra Deck, by banishing monsters from your hand, field, or Graveyard as Fusion Materials.  When this card is sent to the Graveyard:  Target 1 card on the field;  Destroy it.

As of now this card can Fusion Summon "Meteor B. Dragon" and "Buster Flare Finaldrake". Not all that interesting, but being able to do so during either turn is nice. The destruction effect might not trigger when it is used for Fusion Summoning, but it still triggers quite often (milling, hand size limit, regular destruction). This seems quite powerful, so you might want to change it so it only activates when sent from the field to the Graveyard. This way it is still useful for bluffing a back row. In case you chain this card to a mass destruction effect, you still get the benefit(?) of both effects.
 
Also most cards in this archtype seem to return cards to your hand, why not make this card return the target instead of destroying it. That way it supports the archtype better. In most cases, where you target an opposing monster, it would disrupt the opponent either way.
[/spoiler]
[spoiler="The archtype"]
This archtype seems to revolve around summoning powerful monsters, and making them more powerful. Quite unusual nowadays, but that does not matter. Also the returning part of the effects remind me of the "Mist Valley" archtype. As that archtype deals with returning cards to your hand, which can help this archtype. Two specific cards are "Mist Valley Falcon" and "Mist Valley Shaman"; they return the cards to your hand allowing you to Special Summon another "Buster Flare" monster. Since the effect of "Mist Valley Falcon" activates during the Battle Phase, you can use it to declare an additional attack that Battle Phase (return a "Buster Flare" monster to your hand and Special Summon another).
 
I would also like to warn you for a specific card, which can make this archtype extremely powerful "Begone, Knave!". A "Buster Flare" monster you control attakcs and it deals damage to your opponent; since it returns to your hand by the effect of "Begone, Knave!",  you can Special Summon either "Buster Flare Dhampir" or "Buster Flare Rex" (depending on the returned monster). If that monster deals damage to your opponent as well, it returns to your hand, which allows you to summon the other. Now that monster can attack, deal damage and return; Special Summoning the other... I guess you get the point. 
 
With all that being said, I do think this archtype requires little tweaking. It might need some support cards (protection against destruction, ways to get rid of opposing spell/trap cards), but most cards which are (semi-)splashable suffice.
 
I also have a suggestion for a monster, should you ever wish to expand this archtype: An easy summonable monster which, once per duel, can return to your hand when it would be sent from the field to the Graveyard. Since it is returned from the field to the hand, it tirggers the effect of some of the other monsters. Furhtermore it can be somewhat used to stall when you are low on hand cards.
[/spoiler]
 
I hope my suggestions/vision is of some use to you.