Pokémon FireRed and LeafGreen+ is intended to be the definitive FireRed and LeafGreen experience. It adds many quality of life and gameplay conveniences to make the game more bearable to play in 2022, adds more postgame activities, but also maintains the original battle mechanics and Gen 3 feel as much as possible. It's made with the pokefirered decompilation from pret, and I consider it to be complete.