Unlike previous Mainstream Pokemon Games, Hold Items don't exist in this game. Because Hold Items cease to exist - primarily due to the fact that this game is a cross between Pokemon Yellow and Pokemon GO - almost all of the items players can obtain will be used for catching Pokemon. Poke Balls help trainers catch Wild Pokemon, Lures increase the spawn rates of Wild Pokemon, Repels decrease the spawn rates of Wild Pokemon, and Berries help make catching Wild Pokemon easier.
On top of this, healing items (such as Potions and Revives) allow players to take care of their Pokemon when away from a Pokemon Center, Evolution Items (such a Thunder Stones and Moon Stones) allow players to evolve certain species of Pokemon, and Battle Effect Items (such as X Speed and X Attack) allow players to boost their Pokemon's Stats when in battle. From there, Pokemon Candy assists trainers in boosting their Pokemon's Overall Stats, and Mega Stones allow trainers to Mega Evolve certain species of Pokemon. Outside of all of this, the only other items players can find usually are sold to PokeMarts for extra Money.