Television

For fantasy buffs, check out Sam Raimi's 'Legend of the Seeker' 2008-2010 series, one of my favorites.

American Vandal has two seasons on Netflix. It’s a straight faced investigative series of some high school pranks writ large. It’s fucking hilarious.

Grimm is a really good show that I'd never heard of before until somone mentioned it on a thread like this one and I gave it a chance.

Better Off Ted is one of the funniest shows I've ever seen and it pisses me off to no end that it flopped

Pantheon

I’m not sure if it went under the radar or if I just got into it late, but Fringe is a great show that has a lot of interesting twists. I haven’t watched it in a while and I’m planning a rewatch soon.

I randomly came across Dirk Gently's Holistic Detective Agency on Hulu and it quickly became one of my all time favorites. Super interesting characters.

Better Off Ted

The workplace comedy about Veridian Dynamics, the company that can make anything, whether it's a good idea or not.

It was on a major network, but the timeslot kept abruptly changing and the final two episodes were preempted by a live sports event, and never even aired in the US.

Veronica: Ted, we need a mouse that can withstand temperatures of up to 300(?) degrees.

Ted: Live mouse or computer mouse?

Veronica: ....I'll get back to you.

An attempt at creating an artificial meat:

Jerome: It tastes familiar...

Ted: Beef?

Jerome: No...

Linda: Chicken? We’ll take chicken.

Jerome: [Shakes head.]

Ted: What does it taste like?

Jerome: Despair.

Ted: Is it possible it just needs salt?

Carnivale. Too bad it didn't get a proper ending.

Pantheon.

Pantheon.

Seriously, watch Pantheon if you haven’t already. Its screwed up release/licensing (died on the vine on some AMC streaming service) is a crime against humanity.

I literally can't say anything else about it without spoiling it, other than it's some of the best sci-fi ever, and its pacing is fast.

Travelers is quite good and I don't see it being mentioned as much online. Has a lot of ex Stargate extras.

Galavant! The medieval, comedy musical!

Banshee was very good. Some other series that didn't seem to be "big" but I enjoyed are: Hell On Wheels, Mr. Inbetween, Preacher, SAS Rogue Heroes, Tacoma FD and Warrior

The Magicians

Brockmire had some success, but I've never mentioned it to anyone who's actually watched it. The comedy is outrageous, and the characters are awful, but you fall in love with them. It's so good.

The Whitest Kids You Know - Great shortlived sketch comedy show.

As a few other have mentioned Mr Inbetween is the greatest show that America didn't watch.

A Touch of Cloth.

A parody of British police procedurals in the vein of Police Squad/Naked Gun. One of the creators is Charlie Brooker, who also created Black Mirror.

(The title is a pun on the title of a British police procedural called "A Touch of Frost" and the euphemism "touching cloth".)

Person of Interest was a show that started episodic and evolved into an incredibly thrilling epic. Fuck the main actor though.

Not sure how "lesser known" it is, but I can't recommend Final Space enough

Flashforward from 2009. It’s based on a book which is also awesome, but the show really nailed it.

The cast is totally stacked with amazing talent, and the plot/concept is really unique and well-executed. Highly recommend.

The Purge
You, Me & the Apocalypse

The Thick of It, for my unstimulated, laugh-track hating siblings out there. It's 'better' than The Office (both versions), better than Seinfeld (is this even a relevant mention nowadays?), and just under Sunny because Sunny ran for at least 12 extremely solid seasons while The Thick of It is a 3 season show. Strong recommendation for anyone who can process information efficiently!

Kipo and the Age of Wonderbeasts. Western animation series on Netflix. Coming of Age story, post-apocalyptic sapient mutant animals, representation that's neither perfunctory nor performative, inclusiveness triumphing over intolerance, and it occasionally involves a little bit of Kaiju combat. All that and they got a proper ending.

If you are a British millennial then you've probably heard of BrassEye, but everyone else should seek it out. Absolutely hilarious.

I loved the single season of "Surface" that we got in 2005/6. It didn't do well, it wasn't particularly well made, but boy did it have me glued to the TV for the next episode when I was younger.

Detectorists was very well done. It’s a brief 20 episodes over three seasons and a couple specials, and it’s buttoned up so well at the end. Highly recommend!

The Patriot on prime is the best show nobody's watched. It doesn't have a single bad episode, the plot, dialogue, acting and production values are outstanding. It was cancelled after 2 seasons but is still really satisfying. Absolutely love it!