There were in the 1970s and early 1980s some interesting TV series on mainsteam television, some were interesting since they explored areas which are now for the most part dumbed down.
The Omega Factor (1979)
A covert branch of British Intelligence is assigned to investigate the strange, the supernatural, the...'Omega Factor'. During the making of this series there were some real life paranormal events that occurred on site.
Children of the Stones (1977)
Scientist Adam Brake and his son Matthew arrive in the sleepy English village of Milbury to find it under the grip of weird psychic powers unleashed by the sinister village squire, Hendrick, and whose power they struggle to break.
All episodes avaliable via You tube.
The strange friendship among a young boy of the Earth and a extra-terrestrial from the outer space.
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Other episodes available via You Tube
There was a follow on called Chockys Children.