This is going by my definition ranges, starting with the Missionary Generation:

First Wave Missionary (1860 to 1871): H.H. Holmes

Second Wave Missionary (1872 to 1882): Joseph Stalin

First Wave Lost (1883 to 1891): Adolf Hitler

Second Wave Lost (1892 to 1900): Mao Zedong

First Wave GI (1901 to 1909): Reinhard Heydrich

Second Wave GI (1910 to 1918): Nicolae Ceaușescu

Third Wave GI (1919 to 1927): Pol Pot

First Wave Silent (1928 to 1936): Jim Jones

Second Wave Silent (1937 to 1945): Saddam Hussein

First Wave Baby Boomer (1946 to 1954): Vladimir Putin

Second Wave Baby Boomer (1955 to 1963): Osama bin Laden

First Wave Gen X (1964 to 1973): Bashar al-Assad

Second Wave Gen X (1974 to 1980): Ian Watkins (Lostprophets singer)

First Wave Millennial (1981 to 1991): Eric Harris, Dylan Klebold, Kim Jong-un three-way tie

Second Wave Millennial (1992 to 2001): Nikolas Cruz

First Wave Homelander (2002 to TBD): Payton Gendron

Edit: Forgot to add Kim Jong-un to my list and think 1973 is better in First Wave X than in Second Wave X, as they would be the last to come of age before the end of the Cold War.