I love documentaries on subjects that interest me -- animals, wildlife, history, science, human behavior, real life mysteries (though not a lot of real life crime, which I find depressing/upsetting), paranormal speculations particularly around this time of year, you name it, if there's an interesting documentary I'm watching it, usually.
There's a BBC series that's on several times a year, focusing on seasonal changes in wildlife, called Springwatch, Autumn Watch and Winter Watch. It's on live and they show footage of wildlife and follow events happening. It's livelier than it sounds, lol.
I'm currently re-watching The X Files as one of the UK channels are re-running the entire thing daily. Loving that, loved the X Files back in the day too.