In 1993, Dungeons & Dragons manufacturer TSR released the role-playing board game DragonStrike, which was designed to introduce D&D to a wider audience. DragonStrike came with this unintentionally hilarious instructional video. It's the best of the worst of video ephemera.
In 1979, ABC News aired Mission Mind Control, a documentary about the US government's research into the mind control applications of hallucinogens. The documentary is fascinating (albeit depressing), and the 1970s production values give the video a retro flair. [Archive.org]
The first film version of Richard Matheson's zombie apocalypse short story "I Am Legend" came out in 1964 and was called The Last Man on Earth. Luckily it's in the public domain, so you can watch it right here.