I have compiled a list of Godzilla characters-monsters not human or alien races.
Anguirus
Barragon
Battra
Biollante
Destroyah
Ebirah
Gabara
Gigan
Gimantis
Godzilla Jr/Jr/Minya
Gorosaurus
Hedorah
Jet Jagar
Kamacuras
King Caesar
King Ghidorah
King Kong
KumongaManda
Mechagodzilla
Megalon
Moguera
Mothra
Orga
Rodan
Space Godzilla
Spiga
Titanosaurus
Varan
Zilla/Godzillasaurus/Iguanazilla/American Godzilla