This card works well with "Black Rose Dragon". The effect of "Black Rose Dragon" destroys all cards on field so this card can be Special Summoned from your hand while your opponent has no cards on the field.
Activate "Sebek's Blessing" after "Granel" attacks directly to multiply the ATK of "Granel" by 1.5.
Equip this card with "Opti-Camouflage Armor". Then, assuming both players' life points are relatively even, this card could win the duel in about 2 turns.
Similarly, use the effect of "Baby Tiragon" to allow this card to attack directly for massive damage.
If this card is Summoned early in the Duel, an OTK is quite possible with the help of "Limiter Removal" or "Junk Warrior". If your Life Points are at 8000, play "Dark Hole" with "Royal Decree" activated, destroying a monster you controlled (maybe Special Summoned or Summoned the previous turn), and the opponent's monsters. Because a monster is destroyed by an effect you can Special Summon "Granel". Next, use "Junk Synchron" and Special Summon a Level 2 monster in order to Synchro Summon "Junk Warrior". Because "Junk Warrior" increases its attack by the total attack of the Level 2 or lower monsters you control, and since "Granel's ATK" will be 4,000 (8,000 / 2), "Junk Warrior's" ATK will increase to 6,300, letting you perform an OTK.
If you destroy a Synchro Monster in this way, the above "Give and Take" combination can add to the pain.
"Black Brutdrago" makes this combination even more potent in a Deck of Gemini monsters, bringing a potent beatstick of Effect Monster to the field to replace him AND giving you a lot of life.
Alternatively, if you already have a "Granel" out and draw another, you can use "Destruct Potion" to absorb your first "Granel's" attack, gain 1/2 you pre-trap life points or more, and field a "Granel" with even more power.
This card can work wonders in a Scrap Deck as their main focus is Destroying their own cards to destroy their opponent making this card easy to Summon and with it gaining 1/2 of your current LP as ATK and DEF points it can be a deadly threat to handle.
This card can be useful in "Lightsworn" Decks. Since "Judgment Dragon" destroys everything it will most likely destroy another monster you control, allowing you to summon this card. After that you can attack directly with both.
This card can be Special Summoned during the Battle Phase in order to surprise your opponent making your attack less predictable and to add a another attacker your opponent by destroying your monster after attacking.
This card can be useful in "Malefic" Decks since these monsters are easily destroyed by their own effect. You can even force that to happen by Summoning a "Malefic" monster without an active Field Spell.