Porgy and Bess (1959) with Dorothy Dandridge, Sidney Poitier, and Sammy Davis, Jr.
A couple of people have mentioned Americathon. It’s readily available on DVD. It’s sold on DVD-R format but it’s a legit product - the company that owns the rights doesn’t sell it through stores but will make copies for anyone who wants to buy one.
Nothing Lasts Forever has never been officially released on VHS, DVD, or Blu-Ray. I don’t know if it even had an official theatrical release for general viewing. But it’s available on YouTube. (Bill Murray has supposedly said this is his favorite movie that he’s appeared in.)
I’d like to add The_Decline_of_Western_Civilization_Part_II:_The_Metal_Years. I’ve been trying to find a copy forever but it seems it was never released on DVD, except in bootlegs. I don’t think trying to record it off of VH1 would really do it justice.
I’d also like to find Urgh!_A_Music_War. They say this is on DVD but I can’t find a copy of it. I seem to remember something about a format problem is why they haven’t released it, but most people think it’s a copyright issue with the various artists in the movie.
Urgh! on DVD.they burn it for you when you order. No chapter breaks, but it’s all here.
Mine is Scavenger Hunt.Terrible movie, but I still want it.
Kenny & Company I grew up on this wonderful kids’ film. Oddly, long out of print and only available if you really want to shell out the bucks for it.
Unless these out of print movies you’re talking about are also public domain, it’s very likely these are unauthorized bootlegs. Not that I care about people breaking insane copyright laws, but if you do, be forewarned about it. (Yeah I know that post is a few months old, I replied to it anyway)