Pllying order:
KH 1.5+2.5 Collection:
KH Final Mix (2002)
KH Re:Chain of Memories (2004)
KH2 Final Mix (2006)
KH 358/2 Days (2009) [Cutscene movie]
KH Birth by Sleep Final Mix (2010)
KH Re:Coded (2011) [Cutscene movie]

KH 2.8 Collection:
KH Dream Drop Distance HD (2012)
KH X Back Cover (2017) [Movie]
KH 0.2 A Fragmentary Passage (2017)

KH3 + ReMind DLC (2019-2020)
KH Union X (2016-2021) (Shutdown mobile game, cutscenes only) [KHUX Cutscene Playlist] / [Fandub of KHUX Part 1] [Fandub of KHUX Part 2]

KH Melody of Memory (2020) (Rhythm game) [KHMoM Cutscenes]
KH Dark Road (2020-2022) (Mobile game) [KHDR Cutscene Playlist]

Upcoming Unreleased Games:
KH Missing-Link (Mobile game)
KH4
Copy from Reddit @ZeroSora