There haven't been all that many- although if you include governors from before Alaskan statehood the numbers are substantial.

William Allen Egan         January 3, 1959         December 5, 1966         Democratic                  

Wally Hickel         December 5, 1966         January 29, 1969         

Keith Harvey Miller         January 29, 1969         December 7, 1970

William Allen Egan         December 7, 1970         December 2, 1974         Democratic                 
Jay Hammond         December 2, 1974         December 6, 1982         Republican                          2

Bill Sheffield         December 6, 1982         December 1, 1986         Democratic                 
Steve Cowper         December 1, 1986         December 3, 1990         Democratic                         1
Wally Hickel         December 3, 1990         December 5, 1994         Alaskan Independence                 Republican
Tony Knowles         December 5, 1994         December 2, 2002         Democratic                 
Frank Murkowski         December 2, 2002         December 4, 2006         Republican                 
Sarah Palin         December 4, 2006         July 26, 2009         Republican                 
Sean Parnell         July 26, 2009         Incumbent         Republican