The Mysterious Monsters (1975): The 1970s was a big time for allegedly paranormal stuff - cryptozoology, Uri Geller, UFOs, on and on, that piqued my imagination and sometimes scared me, though I wasn't totally convinced. I remember seeing this pseudodocumentary - hosted by TV stalwart Peter Graves - one weekend afternoon and vaguely recall solemn narration and cheesy reenacments of alleged Bigfoot encounters. YouTube shows that, all too often, nostalgia isn't what it used to be.
Sasquatch: The Legend of Bigfoot(1976): I only saw the poster for Sasquatch, with its Bigfoot presented in giant silhouette between trees - and maybe a trailer, with some guys searching for it. The silhouetted image stayed with me and for years I wanted to see it but it was as hard to find as the real critter seems to be. Having checked it out recently, I know now I wasn't really missing out on anything.
The Adventures of the Wilderness Family(1975) and The Further Adventures of the Wilderness Family(1978): I can't recall which one of these I actually saw, but the series (apparently there was a third) focused on a Los Angeles family who decided the pressures of city life were too much and opted for living in the mountain countryside with only the elements, lack of electricity and plumbing, hunger, and wild animals to worry about (if my parents inflicted something like this on me, I'd have run away from home). Only vague memories remain and I've no great desire to revisit this.
Roar (1981): This is one I read a magazine article about but never got to see. Tippi Hedren, who'd starred in The Birds, faced even more danger during the decade or so it took to make this film with her co-star, director and then-husband, Noel Marshall. It was something about people trying to save big cats from poachers but the real thrill was reading about the dozens of injuries, gangrene and other problems that plagued the production (which flopped). It's turned up recently on Blu-ray and excerpts of the cast and crew getting up close and personal with lions and other large, unpredictable and deadly beasts are online - were these people insane? The film cost a bundle and flopped and the marriage ended shortly afterwards (coincidence? I think probably not).