What creatures have the most gil on final fantasy 10-2?

In Final Fantasy X-2, the creatures that drop the most gil are the rare monsters known as "Overdrive" enemies, particularly the "Chocobo Eater" and "Ultima Weapon." Additionally, certain fiends found in the Monster Arena, like the "Dark Aeons," can also yield substantial gil when defeated. Farming these enemies can significantly boost your gil reserves, especially when combined with the right accessories to increase gil drops.