#1. Ken Shamrock won the King of the Ring tournament in 1998
Ken Shamrock beat The Rock to win the King of the Ring tournament in 1998, but no one ever really thinks of that when they hear the name 'Ken Shamrock' which is a shame.
As well as beating The Rock, Shamrock defeated two more Nation of Domination members in Mark Henry and Kama, as well as Jeff Jarrett, to win the tournament. However, Shamrock didn't then start calling himself 'King Shamrock'.
Shamrock didn't really go on to achieve much as the reigning King of the Ring winner other than feuding with another former winner who was still calling themselves king, King Mabel.
Eventually, Shamrock just stopped being the reigning King of the Ring altogether and the title was officially dead when he joined Vince McMahon's new heel stable, The Corporation.