Kingdom Hearts music!

[without_reason]

KH:358/2 - Xion's theme (MAJOR MAJOR SPOILERS in comments and related videos section)
In-game version
Arrangement by BlueNctrn
10 minute-long version (with Jakah016's arrangement)
Piano arrangement by HypochondriacPiano
Piano arrangement by DannyxDarko13
Piano arrangement by krabwalkin
R&B remix by ImUnlikeAnyOther

KH:358/2 - Second-to-last boss theme (MAJOR SPOILERS)
In-game version
Arrangement by Jakah016
Arrangement by MilenPetzelt15
Rock remix by sasukeshika

KH:358/2: Final boss battle (SPOILERS)
KH:358/2: The World that Never Was (CELLO <3)
KH:358/2: Dearly Beloved (My favourite version; seems like it gets better with every KH game!)

KH2:FM+: CoM Organization XIII Data/AS battle
KH2:FM+: Cavern of Remembrance (also KH:358/2's Mission Mode menu theme)
KH2:FM+: Cavern of Remembrance battle
KH2:FM+: Terra battle

KH:BBS: Wheel Master battle - 10 minute-long version (with BlueNctrn's arrangement)
KH2/CoM/Days: Sinister Sundown arrangement by BlueNctrn