Only one player in NBA history has played against every team of a conference in the playoffs. That man is Derek Fisher. He also beat every single one.

Derek Fisher, iconic GSW point guard, has played against every western conference team in the playoffs, and beaten them. There are men and there are legends, but no other player in league history has even played against all the teams in a conference, let alone beat every single one,

*** SINCE the NBA has been a 30 team league ***.

LAL vs DAL First Round 2012	LAL vs DEN First Round 2008	UTA vs GSW Semi-Finals 2007
LAL vs HOU First Round 1999	OKC vs LAC Semi-Finals 2014	OKC vs LAL Semi-Finals 2012
OKC vs MEM First Round 2014	LAL vs MIN First Round 2003	LAL vs NOH/NOP 1st Round 11'
LAL vs OKC First Round 2010	LAL vs PHO Semi-Finals 2000	LAL vs POR Conf. Finals 2000
LAL vs SAC First Round 2000	LAL vs SAS Conf. Finals 2001	LAL vs UTA Semi Finals 2008

And here's a bonus series of Fisher beating down the soon un-defunct Seattle Supersonics, to put him at 16 teams beat in the playoffs. Even if the NBA adds more teams soon, it's hard to envision anyone eclipsing this accomplishment for a very long time, as a player would have to have extreme longevity, success, and play on at least 2 different successful playoff teams, without changing conferences.