Early Japan: The Three Treasures
1954: Godzilla
1955: Half Human
1955: Godzilla Raids Again
1955: Rodan
1957: The Mysterians (gives humanity space travel by using reverse engineered Mysterian tech)
1958: Varan
1958: The H-Man
1960: The Human Vapour
1961: Mothra
*1961: Frankenstein vs Baragon
1962: King Kong vs Godzilla
1963: Matango
1963: Atragon
1964: Mothra vs Godzilla
1964: Dogorah
*1965: Ghidorah: The Three Headed Monster
*1965: Battle in Outer Space
*1966: Invasion of Astro-Monster
1966: Ebirah: Horror of the Deep
1966: War of the Gargantuas
1967: Son of Godzilla
*1967: King Kong Escapes
1969: All Monsters Attack (explained below)
1969: Latitude Zero
1970: Space Amoeba
1971: Godzilla vs Hedorah
1972: Godzilla vs Gigan
1973: Godzilla vs Megalon
1973: Zone Fighter
1974: Godzilla vs Mechagodzilla
1975: Terror of Mechagodzilla
1988: The War in Space
1999: Destroy All Monsters
*1979-1982: Gorath (the moon is somehow replaced). Gorath can only be included in the continuity if you really want it included for completion's sake. If you go strictly on what information is given in the movies, it is too incompatible. People believing Kong is a legend in KKE is one thing, but the destruction of the moon is too big to overlook.
Added in 5 minutes 47 seconds:
Ivo-goji wrote:They wouldn't have to get a moon from another planet if Gorath's debris trail delivered it for them.
Oh right! That's also a good, and more plausible, theory.
But it still relies on too much information that isn't in any of the movies. Gorath might have to stay off to the side to be included or excluded on an individual level. I personally include it, but I also agree with those who dont.