Space: Above and Beyond. It was a short-lived show on FOX about a group of space marines that are pressed into service against an alien menace, but not everything is as it seems. The show was a a bit of a mashup between Aliens, Blade Runner, and Starship Troopers, and it was awesome. If there was ever a show that needed a remake, it's this one.
Science Fiction
This magazine is aimed at fans and creators of sci-fi and related media of all kinds. It includes all content related to the sci-fi genre and only content related to the sci-fi genre. The goal is to build a community for everyone who enjoys science fiction and related topics. This includes the obvious books, movies, and TV shows, but also original writing, the discussion of writing SF, futuristic art and designs, and the science and technologies that inspire the sci-fi genre. **Team Top 20**
This sounds like a Warhammer 40k tv show by your description! I'm gonna have to check this one out and be disappointed when it ends far too early. :(
Serial Experiments LAIN. It's a 13 episode anime, in a "future" where everyone is connected to "The Wired" via wireless devices. For a 1998 anime, it is highly prophetic. It even predicts the idea of people having completely different identities in real life then they have online, and does a great job musing on the blurry line between the internet and the real world.
I really enjoyed Dark Matter. It got a little wild as the story went on, but the premise was very good, and I enjoyed a lot of the characters. (Especially the Android)
Electric Dreams
I found these to be super enthralling and well made.
IMDB short summary, "Philip K. Dick's Electric Dreams" is a 10-episode science-fiction anthology series that journeys into unique worlds beyond the reach of the imagination. Based on short stories written by Dick, each stand-alone episode is inspired by a different story.
Without a doubt, Doctor Who.
They Live: John Carpenter's documentary about what yuppies and Republicans have been doing to America since 1980.
Farscape has been covered, so to bring up something that definitely hasn't been mentioned, Charlie Jade. A Canadian/South African co-production from the 2000s about three parallel Earth versions of Cape Town colliding. Awesome show, but I don't think I've ever met anyone who knows it.
I was mad obsessed with Dollhouse and Fringe. It felt like both ended way too soon, but at the same time they didn't outstay their welcome as so many shows do.
Probably doesn't count as 'lesser known' but my answer is Galaxy Quest