I do not actually own any of these soundtracks, so matching MIDIs to track names is mostly guesswork. Anyone who can confirm my choices, or identify any MIDIs which I have been unable to match to the corresponding track title, please do so!
Final Fantasy I + II, All Sounds Of (Buy it!)
Released: December 1988
The original sound version of FF1 and 2 combined. Total of 49 tracks: 20 from FF1, 23 from FF2, 4 unreleased tracks, and 2 arranged tracks.
Final Fantasy III Original Sound Version (Buy it!)
Released: July 1991
44 tracks from FF3.
Final Fantasy IV: Original Sound Version (Buy it!)
Released: June 1991
44 tracks from FF4.
Final Fantasy V: Original Sound Version (Buy it!)
Released: December 1992
A total of 67 tracks from FF5 spread over two CDs.
Final Fantasy Mystic Quest Sound Collection
Released: September 1993
28 tracks from FFMQ, including one remixed track. The music was composed by Ryuji Sasai and Yasuhiro Kawakami.
Final Fantasy VI: Original Sound Version (AKA Kefka's Domain) (Buy it!)
Released: March 1994
A total of 61 tracks from FF6, spread out over three CDs. This was released in the U.S. as "Kefka's Domain".
Final Fantasy Wind And Fire
Released: May 1994
31 tracks (including one vocal) from the first two episodes of the Final Fantasy anime.
Final Fantasy Dragon And Star
Released: July 1994
22 tracks from the last two episodes of the Final Fantasy anime.
Final Fantasy Tactics Original Sound Version
Released: June 1997
71 tracks from FF Tactics spread out over two CDs. Music composition by Masaharu Iwata and Hitoshi Sakimoto.
Final Fantasy VII Original Sound Track (Buy it!)
Released: February 1997
85 tracks from FF7 spread out over four CDs.
Final Fantasy VIII Original Sound Version (Buy it!)
Released: March 1999
74 tracks from FF8 spread out over four CDs.
Final Fantasy IX: Original Soundtrack (Buy it!)
Released: August 2000
110 tracks spread over 4 CDs, including a vocal song, an a capella version of said song, and the songs from the FF9 Coca-Cola commercials.
Final Fantasy IX: Original Soundtrack Plus
Released: December 2000
42 tracks from FF9; these tracks were from FMV sequences and were not released on the main soundtrack. A few other tracks (like "Rufus's Welcoming March" and the FF9 version of "Let Me Know The Truth" from FF3) have been included, as well as outtakes, unreleased tracks, and a bonus "Silent Version" of Melodies Of Life.
Final Fantasy: The Spirits Within: Original Soundtrack
Released: July 2001
18 tracks (19 in Hong Kong version, 20 in Indonesian version) from the movie Final Fantasy: The Spirits Within, including two vocals sung by Lara Fabian and L'arc en Ciel.
Final Fantasy X: Original Soundtrack (Buy it!)
Released: August 2001
91 tracks spread over 4 CDs, including a vocal song and an orchestrated version of the same song.
FF: Unlimited Music Adventure Verse.1 (Buy it!)
Released: December 2001
32 tracks from the first season of the FF Unlimited anime, including vocal tracks by Kana Ueda and FAIRY FORE.
FF: Unlimited Music Adventure Verse.2 (Buy it!)
Released: April 2002
37 tracks from the FF Unlimited anime, including several tracks from the first soundtrack, and all three vocal songs.
FFXI Original Soundtrack (Buy it!)
Released: June 2002
51 tracks over 2 CD's from Final Fantasy XI.
FF1+2 Original Soundtrack (Buy it!)
Released: October 2002
65 tracks over 2 CDs, from the PlayStation remakes of FF1 and 2. It includes some extra music added for the new release, but does not include the unreleased tracks of the original original soundtrack. 8-)
Final Fantasy Unlimited Before
This drama CD was packaged with the FFU Japanese DVD boxset.
Final Fantasy Unlimited After 2
Released: December 2002
This is an audio continuation of the FFU After book, itself a continuation of the FFU anime series. It contains 6 audio tracks.
Final Fantasy Tactics Advance Original Soundtrack (Buy it!)
Released: February 2003
74 tracks over 2 CDs, from FFTA. The first CD is original game music, the second is arranged versions.
Final Fantasy X-2 Original Soundtrack (Buy it!)
Released: March 2003
61 tracks over 2 CDs, from Final Fantasy X-2.
Final Fantasy XI: Vision of Zilart Original Soundtrack (Buy it!)
Released: May 2003
19 tracks from the "Vision of Zilart" expansion for FF11.
Final Fantasy Crystal Chronicles OST (Buy it!)
Released: August 2003
52 tracks on 2 discs from the game FF: Crystal Chronicles.
FFX-2 International+Last Mission Original Soundtrack (Buy it!)
Released: February 2004
10 tracks from Final Fantasy X-2 International+Last Mission, containing the US versions of the vocal songs and some music from the Last Mission sidequest.
Final Fantasy XI: Chains of Promathia Original Soundtrack (Buy it!)
Released: November 2004
24 tracks from the "Chains of Promathia" expansion pak for FF11.
Final Fantasy VII: Advent Children Original Soundtrack (Buy it!)
Released: September 2005
Two discs of music from the movie FFVII: Advent Children
Final Fantasy VII: Dirge of Cerberus Original Soundtrack (Buy it!)
Released: February 2006
Two discs of music from the FFVII: Dirge of Cerberus. There is also a limited edition that comes in a DVD case, with the soundtrack, "REDEMPTION" single, and the game itself. Vincent is pictured on one side, Gackt on the other.
Final Fantasy XI: Treasures of Aht'Urhgan Original Soundtrack (Buy it!)
Released: May 2006
21 tracks from the "Treasures of Aht'Urhgan" expansion pak for FF11.
Final Fantasy XII: Original Soundtrack (Buy it!)
Released: May 2006
100 tracks on four discs (in a DVD-style fold out case) from Final Fantasy XII.
Final Fantasy III: Original Soundtrack (Nintendo DS)
Released: September 2006
Contains music from FF3 DS as well as some arranged tracks not found in the game. Also includes songs that weren't with the original FF3 (for NES). Includes a DVD (region 2) with the game's opening sequence, promotional video, and interviews.
Final Fantasy Crystal Chronicles: Ring of Fates Original Soundtrack
Released: September 2007
57 tracks from the Nintendo DS sequel to FF: Crystal Chronicles, Ring of Fates.
Crisis Core: Final Fantasy VII Original Soundtrack
Released: October 2007
Music from Crisis Core: Final Fantasy VII for the Sony PSP.
Final Fantasy Tactics A2: The Sealed Grimoire Original Soundtrack
Released: November 2007
Music from Final Fantasy Tactics A2 for the DS.
Final Fantasy 7: Before Crisis & Final Fantasy VII:Last Order Original Soundtrack
Released: December 2007
Music from the cellphone RPG Before Crisis: Final Fantasy VII. Also includes the "Last Order" BGM portion of the music included with the previously released limited edition "Final Fantasy Advent Children" box set.
Final Fantasy IV: Original Soundtrack (Nintendo DS)
Released: January 2008
Includes music from the remake of Final Fantasy IV for the Nintendo DS. Also includes a region 2 DVD with interviews from Nobuo Uematsu, Kenichi Fukui, Junya Nakano, and others.
Final Fantasy XI: Wings of the Goddess Original Soundtrack
Released: April 2008
25 tracks from the "Wings of the Goddess" (also known as "Divine Soldiers of Atlana") expansion pack for FF11.