The Undertaker had major matches and they were at least 9 major matches.
November 27, 1991- Mark defeats Hulk Hogan to win his first WWF World Championship.
March 23, 1997- Mark defeats Sid Vicious to win the WWF World Championship for the second time.
June 28, 1998- Mark defeats Mankind in one of the WWF's most famous cage matches.
July 26,1998- Mark teams up with Stone Cold Steve Austin to win the WWF's tag team title.
May 23, 1999- Mark defeats Steve Austin to win his third WWF World Championship.
April 17, 2001- Mark teams up with Kane to win the WWF Tag Team Championship.
August 7, 2001- Mark and Kane win the WCW Tag Team Championship.
August 19, 2001- Mark and Kane win their second WWF Tag Team title.
December 9, 2001- Mark defeats Rob Van Dam to win the WWF Hardcore Championship.
Now, their is another one to add to this list, his win over Batista for the World Heavyweight Title at Wrestlemania 23.