>>6356110God, that's an impossible question to answer. I would say, unless you're willing to watch his entire match history in order (which is a lot but you won't be disappointed) try to watch some from each (loosely defined) "era" in his career.
>underdog babyfacevs. Hansen 1991
vs. Williams 1994
>AJPW acevs. Taue 1996
vs. Misawa 1998
>NOAH acevs. Akiyama 2000
vs. Takayama 2004
It's really hard to recommend just matches with how centered King's Road was on long running feuds that span across multiple tag matches and stuff. Everyone talks about his final match against Misawa, but I genuinely think you don't appreciate it even half as much if you haven't seen at least a good bit of their tag and singles history up until that point. Maybe start with those, but I would recommend looking into the Pillars as a whole, chronologically, to appreciate the big matches more.