quetzalcoatl is the one i summoned a lot in FF8 to get me through the game before i understood how insanely broken the junction system and limit breaks were so i have a lot of fond associations
very very few card games even! if you just want to get overpowered as fast as possible you just need to refine the zell card into hyper wrists and the quistis card into samantha souls and the game is over, especially if you don't level up