Ummm. Therein lies the difficulty, I think, Marky. While all of these films do indeed have a "cult" following, they're all well-known far beyond such a limited audience; I'm not sure they'd fall into the normal usage of the term "cult", because of that... and the fact that they all had a rather large budget (save for Night of the Living Dead, The Hills Have Eyes, and From Dusk Till Dawn ... and even the last of these, comparatively speaking, had a rather good budget) and had -- again, save for those three -- considerable advertising and promotion. And, with the exception of Beastmaster, they've all had quite a lot of critical acclaim, as well.
Hmmmm.... I'm not quite sure what to call these, but I think -- at least over here -- use of the term "cult film" would have considerably different connotations... think Atomic Submarine; Santos vs. [fill in the blank]; Scorpio Rising (Kenneth Anger); the films of Mario Bava, Lucio Fulci and (though he's always had a fair amount of acclaim) Dario Argento -- and, again, the critical acceptance of these, now that the original director's version is available, makes it problematic to call them "cult" films at times....