If we're going by real-world standards, Elio's favorite fruits are ones usually grown in the Caribbean, such as:

🍊<Bananas>

🍊<Mangos> (Especially if it comes with Hot Sauce 😋)

🍊<Tangerines>

🍊<Guavas>

🍊<Cantelope-Melon Blends> (Especially when topped with Honey 😋)

However, if we're talking about him as a Pokemon OC, his favorite "fruits" (i.e. berries) would be:

🍅<Enigma Berry> (🥇; "Overall Best Tasting Fruit" in his book. His immediate go-to. 😌)

🍅<Nanab Berry> (🥈)

🍅<All of the Damage-reducing Berries> (🥉; Excellent as a smoothie ingredient or tea blends when dried)

🍅<Silver Razz/Silver Pinap Berry> (🏆; "Most Aesthetically-Pleasing Fruit" 🤩)

🍅<Golden Razz/Golden Pinap Berry>