Pokemon Frontier Adventure (Pokemon Emerald Hack)

This romhack, known as Pokémon Frontier Adventure, is an attempt to improve the basic combat experience of the regular game by incorporating the Pokémon Emerald Battle Engine Upgrade while also consolidating and highlighting the game’s optional side quests and activities.

Features

• Use your skills to collect all 7 Gold Symbols of the Battle Frontier, utilizing Pokémon and mechanics from Gens I-VII
• Become a Master Coordinator in the Contest Hall, mixing berries and dazzling audiences with your Pokemon
• Spend your off-time at the Game Corner, trying to win enough BP to cover that next big purchase without any battling
• Save up enough BP to buy stronger Pokemon and items. Use them to win enough to earn decorations for your Secret Base

Source: https://www.pokecommunity.com/showthread.php?t=442844