Pokemon Sako is a good Pokemon Fire Red Hack but it isn’t fully completed. The author of it was busy so it has slowly been progressing.
Pokemon Shattered Dreams is a great Pokemon Fire Red Hack made by Quilava’s Master who is the author of other Hack Pokemon Requiem. With its features, you will love it.
Pokemon Rebirth is an awesome Pokemon Emerald Hack which is made by Link2999 for GBA Emulators. This game is still in process of developing.
Pokemon Pure Gold is another Pokemon Gold/Silver/Crystal Remake with GBA graphics because ZodiacDaGreat uses Pokemon Ruby engine to make it. The game has been progressing.
Pokemon Palladium is an interesting Pokemon RPG Hack with beautiful GBA graphics and great features. It is so worth to try it out.