Don’t leave out the spiders, as in “Tarantula” (1955) and “Earth vs. the Spider” (1958). Heck, I seem to even recall Tarzan battling a big old spider in a cave in one of his 1940s-era films.
My gosh, but I used to love all the old creature-feature/sci-fi type films that all the local channels used to air. Whether saturday afternoons, or weekend late-shows, or even weekday, after-school “Dialing for Dollars Theaters,” those things were such a joy. Absolute bliss, for a wide-eyed youngster.
Another giant...The Black Scorpion That was more than likely about that same time frame, and who was cast. No idea, would need to look it up.