In the beginning of the series, Yuma's Deck was very basic containing a random assortment of monsters with no central strategy tying them together. However, as he gathers the "Numbers," Yuma's Deck slowly matures, especially after he receives cards from the Duel Sanctuary.
When Yuma's opponent is not wielding a "Number" or "Chaos Xyz" card themselves, Yuma often refrains from using his "Numbers". but is willing to Summon "Utopia" if the opponent demands it. In such situations, the "Djinn" Xyz Monsters or "Heroic Champion - Excalibur" are often his go-to choices.
Yuma originally uses a Number/Syllable Deck. It is supported with a lot of ATK increasing cards such as "Wonder Wand" and Trap Cards which protect his monsters from destruction such as "Bye Bye Damage". It contains some support for his "Gagaga" monsters later on.
This Deck was later replaced by a new version after Yuma received a large amount of new cards from Roku when he defeated Kaze and protected the Duel Sanctuary.
In the finals of the World Duel Carnival, Yuma debuts more non-"Number" Xyz Monsters, "One-Eyed Skill Gainer" and "Gagaga Cowboy". His WDC profile lists his Deck's name as "Xyz One Turn Kill" as he heavily focuses on using Xyz Monsters and normally wipes out of his opponent's remaining Life Points in the final turn. In addition, as Yuma dealt with more dangerous opponents, he relies heavily on augmenting his "Number C39: Utopia Ray" with abilities of his "ZW -" monsters through the power of ZEXAL than he did before.
After defeating Nash, Astral obtained all 100 "Numbers", thus preventing Yuma from using them in their Duel. Thus, Yuma modified his Deck before the Duel. The Deck focuses on "Gagaga" monsters and support. During the Duel he would later get a new Ace Monster called Number F0: Future Hope.
In the Aim For Number 1 in the World! non-canon episode, his Deck appears similar to his usual anime Deck, including "Number" monsters. He also Dueled Astral in an explanation Duel at the beginning of the special.