Doctor Who, UFO, Space 1999, Red Dwarf. Only seen a clips from most of them. I especially don't get Doctor Who (though I've never seen a complete episode).
The Brits are better at TV horror & suspense, like Thrillers.
you should consider Blake’s 7
most say you should just start with episode 2, then watch the first one at the end of the series if you want.
or just skip first season
https://www.youtube.com/watch?v=g8n6D78ePU0
https://www.youtube.com/watch?v=9SEC_CNI7Wk
https://www.youtube.com/watch?v=UC-D_HP00r4