Several themes are known and loved throughout the series. Some have stayed more or less the same; others have been completely redone. I don't have every single MIDI, but I have enough to get an idea of what the music of this series has gone through.
FF: Prelude
The original theme, from FF2, only contained half of what I consider the "base" theme.
FF2: Chocobo!
FF3: Chocobos!
FF4: Chocobo-Chocobo (yellow), Samba de Chocobo (black)
FF5: Go-Go Boco! (yellow), Mamba de Chocobo (black)
FF6: Techno de Chocobo
FF7: Waltz de Chocobo (Chocobo dancing!), Electric de Chocobo (battling Chocobos!), Cinco de Chocobo (riding Chocobos), Fiddle de Chocobo (racing Chocobos!)
FF8: ODEKA ke Chocobo (Chicobo theme), Modes de Chocobo (riding theme)
FF9: Aloha de Chocobo, Ukelele de Chocobo (riding Chocobos)
FF10: Chocobo Jam [Brass de Chocobo]
FF1: Victory Fanfare
FF2: Victory Fanfare
FF3: Fanfare
FF4: Fanfare
FF5: Victory's Fanfare
FF6: Fanfare
FF7: Fanfare
FF8: The Winner
FF9: Fanfare
FF10: Victory Fanfare
FF1: Main Theme
FF2: Main Theme
FF3: Eternal Wind
FF4: Main Theme
FF5: Four Valiant Hearts
FF6: Terra, Searching For Friends
FF7: FFVII Main Theme
FF8: Blue Fields
FF9: Over The Hill
FF10: N/A
FFMQ: World
FF Tactics: World Map
FF1: Battle Scene
FF2: Battle 1
FF3: Battle 1
FF4: Fight 1
FF5: The Battle
FF6: Battle Theme
FF7: Fighting
FF8: Don't Be Afraid, The Man With The Machine Gun
FF9: Battle 1
FF10: Battle Theme
FFMQ: Battle 1
FF2: Battle 2
FF3: Battle 2
FF4: Fight 2, The Dreadful Fight
FF5: The Fierce Battle, The Decisive Battle
FF6: The Decisive Battle, The Fierce Battle
FF7: Still More Fighting
FF8: Force Your Way
FF9: Battle 2
FF10: Enemy Assault
FFMQ: Battle 2
FF1: Airship
FF2: The Airship (unreleased track)
FF3: Go Above The Clouds!, The Invincible
FF4: The Airship
FF5: The Airship
FF6: Blackjack
FF7: The Highwind Takes To The Skies!
FF8: Ride On
FF9: Airship ~ Hilda Garde
FF10: Launch
FF3: This Is The Last Battle
FF4: The Final Battle
FF5: The Last Battle
FF6: Dancing Mad Part 1, Part 2
FF7: One Winged Angel
FF8: The Extreme
FF9: The Final Battle
FF10: Final Battle
FFMQ: Battle 3
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Final Fantasy Chocobo's Dungeon Moogles Figure Key Chain Banpresto JAPAN
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Final Fantasy 6 VI Moogles MOG Figure Ballchain FF Swing Bandai SQUARE
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