What are some lesser-known obscure TV series that went under the radar, that you would recommend?

I’m going to recommend the 1970s BBC series “Survivors”. It’s kind of like Walking Dead lite, without the zombies.

Avoid the 2000s remake though. It’s ridiculous.

I also recommend the 1971 BBC series I mentioned in another thread, about a futuristic fascist government in Britain: “the Guardians”.