As many films as there are available on TV and for home viewing, they are only a small percentage of the movies that have been made. Most of the others will never be available on DVD, for one reason or another. Some sound just plain awful, while others could be called intriguing, like the 1969 film Troika!
In the film's final segment (which sounds awesome) an eight-foot high insect wandering a Martian landscape is attacked by blue-skinned aliens (led by NBA All-Star Nate Thurmond) as a cowboy plays Wabash Cannonball.
There are 24 films in this list at io9. Link