Atragon (1963)
When an ancient underground civilization and their snake like guardian plots to reclaim the surface world, those of the surface fights back
Frankenstein Conquers the World (1965)
Near the end of WWII, Germans transport the immortal heart of Frankensteins monster to Japan, where it is seeming lost in the bombing of Hiroshima Years later a wild boy is found, born from the immortal heart
Son of Godzilla (1967)
A reporter stumbles upon weather experiments on a tropical island, discovering giant mantids, a cast away woman, and an infant monster that Godzilla must adopt and learn to raise as one of his own
King Kong vs. Godzilla (1962)
A UN reporter broadcasts a report on the appearance of a prehistoric monster that emerges from hibernation while a pharmaceutical company seeks publicity with a monster of their own US Version