Re: What Were The Most Useful Summon Creatures For You In All "FF" Titles?
In Final Fantasy II/IV, I actually found the Sylph, those little faeries, very useful. They would heal the group as they attacked, syphoning life from the enemy to your party. At one point, my entire party had been killed by the lunar leviathan except for Rydia. She killed it with only the help of the Sylph.
The rare bomb spell was very powerful and grew in power as Rydia's level increased.
Bahamut was just epically powerful.
Perhaps it has been too long since I played Final Fantasy III/VI, but I seem to think many of the Espers were too similar.
In Final Fantasy X, Bahamut is so powerful and is acessable earlier in the game than the Dark summons. Anima is probably the strongest for the short battles. The Magus sisters are so amazingly powerful, yet more difficult to control. Valefor is great too, especially against enemies that can't hit him in the air and even more so when you find his second, hidden, attack.