Rock and Roll
Gallant Granite is a generic searcher that can work in any deck. As most decks run Level 4 monsters to Xyz Summon cards like Abyss Dweller, this card is another option for your Rank 4 plays. Another card run by most decks in either their Main or Side is Nibiru, the Primal Being. If you aren't drawing into Nibiru when you need it, Granite can search "The Rock" with his first effect. This would also inform your opponent that you have Nibiru in your hand, but they might not have a way to stop it.
The first effect can also search Block Dragon, who can protect Granite when Special Summoned. You could choose to use both monsters as Link Material to take advantage of Block Dragon's GY effect. A great card to Link Summon with these two monsters is Missus Radiant. As an EARTH monster, it has synergy with Rock monsters. Radiant can not only open your Field up for further Extra Deck plays, but also recur Granite from your GY if it is destroyed.
No Stone Unturned
Fossil Dyna Pachycephalo is another powerful target to search with Granite. By finishing your combo with Saryuja Skull Dread, you can use its effect to summon Fossil Dyna in your hand. This would effectively lock both players out of the majority of their plays after you have set up your Saryuja. An uncommon use of Granite's second effect would be to Set Fossil Dyna from your Deck instead. After this, you could finish your combo with Book of Taiyou to resolve Dyna's effect on being flipped face-up, the same turn it was Set.
The second effect of Gallant Granite also enables monsters like Pot of the Forbidden. This card has a Flip effect that allows you to activate one of four powerful effects. It is another card that can extend your plays if combined with Book of Taiyou. Depending on the matchup, each effect would give you the advantage. In the same turn you summoned Granite, you could nuke your opponent's monsters or backrow, or shuffle a hand trap back into their Deck.
Rock in a Hard Place
Granite can be added to decks that use other Rock Xyz monsters, such as Thunder Dragons. Along with Batteryman Solar, Level 4 Watt monsters help to Xyz Summon into Granite more consistently. If you want to learn what Watts can do for this deck, check out our previous article here. Another Rank 4 Rock to use alongside Granite is Daigusto Emeral. This monster shuffles three Thunder Dragon monsters from your GY into the Deck, then lets you draw another card.
Number 68: Sanaphond the Sky Prison is a Rank 8 Rock that is easy to access with two Thunder Dragon Colossus on your Field. This card locks down summoning from the GY - cutting off valuable resources from a deck like Salamangreat. To this end, Rock Xyz monsters like Gallant Granite become valuable components of the Extra Deck.
In summary, Gallant Granite is a generic Rank 4 Xyz and a searcher for powerful cards like Nibiru. It also assists in defensive Rock strategies and works well with Rock Xyz monsters already used in meta decks. As long as your deck can summon two Level 4 monsters, Granite will always be an option. However you use Gallant Granite, victory is only a stone's throw away.