The Saturday Superstar Movie does have a case for Lost Media
while some are found like Popeye Meets The Man Who Hated Laughter (though it was upload in parts on YouTube), Tabitha and Adam and The Clown Family, The Banana Splits in Hocus Pocus Park, Daffy Duck Meets The Groovie Goolies (though recobbled with the missing "Mad Mirror Land" scene), Hanna-Barbera's "Lost in Space" pilot and The Mini-Munsters and some are commercially available like The Brady Kids on Mysterious Island, The Adventures of Robin Hoodnik, Oliver and the Artful Dodger, Mad Mad Mad Monsters and Yogi's Ark Lark
i found a piracy website with nanny and the professor, gidget meets the wrong connection, and the red baron while looking for the steven universe movie