Namesakes
Characters in Norse Mythology:
1 character
Gunnar (a.k.a. Gunther) (m) 
Notable Actors and Entertainers:
1 actor
Bill Skarsgård (a.k.a. Günther) 1990-
Notable Athletes:
1 track
(track) Günther Weidlinger 1978-
Notable Musicians:
2 singers
G. G. Anderson (a.k.a. Günther) 1949-
Patrick Lindner (a.k.a. Günther) 1960-
Olympic Medalists:
2 bronze, 1 silver
(bronze) Günther Haase 1952 diving - platform
(bronze) Günther Steines 1952 4x400 m relay
(silver) Hans-Günther Vosseler 1972 swimming - 4x200 m freestyle relay
Other Royalty:
1 prince
August Wilhelm of Prussia (a.k.a. Günther) 1887-1949 Prussia
Saints:
1 blessed
Blessed Gunther of Bohemia 955-1045