There are 13 games in the Kingdom Hearts timeline.
Top 100 RPGs of All Time
How to Play the Tomb Raider Games in Chronological Order - IGN
Kingdom Hearts - IGN
Kingdom Hearts - IGN
Mini Games Guide - Kingdom Hearts 3 Guide - IGN
Kingdom Hearts HD II.8 -- Final Chapter Prologue [Gameplay] - IGN
How to Play the Kingdom Hearts Games in Order - IGN
Kingdom Hearts 4 and Kingdom Hearts 20th Anniversary - Official Announcement Trailer
Kingdom Hearts III - IGN
Don't Let IGN Play or Even Talk about Kingdom Hearts
Every IGN Kingdom Hearts Review So Far
To anyone who may be here to figure out where to start, do not follow this article's advice : r/KingdomHearts
Kingdom Hearts RE: Chain of Memories - IGN
Kingdom Hearts: Melody of Memory Review - IGN