Ooh, ooh, this is a perfect topic for me. I'm going to start with
- Darker than Black (one of the few series I have watched recently)
well, crap
I'm glad you liked it, though, as it's one of my favorites and I seriously cannot say enough good things about it. Also very good taste with Perfect Blue.
I can think of a few really good ones to recommend, but as you requested things that aren't already super-popular, I'll try some others. There are also some that I think are fantastic that probably won't align with your taste so I'll also omit those.
Based on your listed preferences, the first one to jump out to me as a good recommendation is
Psycho-Pass, which is sort of like a darker cyberpunk Darker Than Black mixed with Minority Report.
In a world where computers can accurately scan one's mental state, the government keeps close tabs on every person's likelihood of committing a crime and restricts the freedoms of people who might be a threat to society, as well as attempts to treat them to help them safely integrate back into the rest of the world. Guns are now tied to this "cymatic scan" and will only fire at someone whose crime coefficient is high enough to warrant enforcement action. The story follows a team of detectives and explores the morality of such a world.
Why you'd like it:
- Interesting cast of mostly adult characters (including a cool dynamic between an adult father/son team)
- Novel take on some cyberpunk themes
- Actually pretty thought-provoking, especially if you like literary and historical allusions
Caveats:
- After the first few episodes, the pacing slows down for a bit which is kind of annoying but when it picks back up, the series really hits its stride and stays very strong all throughout.
Next up is a pretty weird but solid choice,
Eden of the East (Higashi no Eden).
A guy suddenly wakes up in front of the White House, naked, carrying a handgun and a cell phone linked to a bank account with over a million yen in it and he has no memory of who he is or how he got there. He soon finds himself embroiled in a conflict with several other individuals who are on a quest to "save Japan" at any cost -- and his past self has done something to seriously piss them off. The story follows his struggles to figure out why he erased his memory and what he did, as well as to come out on top of this contest where money is power and the goal is to rescue Japan from its worsening state of financial recession.
It's hard to really sell Eden of the East because what makes it so good is just how damn well executed it is. Seriously, just watch the first episode even if you have no intention of watching the rest of the series. It has the most compelling first episode I've seen in a long time and it conveys how great the writers are at writing charismatic, likeable characters.
What you'd like it:
- Pretty laidback story with a good amount of drama, mystery, and spectacle, without really becoming grimdark.
- One of the only anime where the cast is written like human beings and is really amicable and fun to watch.
- The opening is by Oasis and it's beautiful.
- There's a dude with a dog.
Caveats:
- None, really. It's a solid 11-episode series that's mostly lacking in anime BS. I've had a lot of success showing it to friends who don't otherwise watch anime.
Onto a very recent one. This I thought was pretty good but not amazing, yet I think it'll fit your tastes a little better than mine:
Aldnoah.Zero.
When the US landed on the moon, they found something more than they expected: a hyperspace gateway to Mars. This led to the human colonization of Mars and the subsequent discovery of some super-advanced technology called Aldnoah, which the Martian settlers monopolized and used to catalyze a cold war between Earth and Mars. Now, in the present, the mounting tensions are coming to a head. Aldnoah.Zero is a mech series, sort of, but it mostly focuses on the pilots and their interpersonal conflicts and their feelings toward the war.
Why you'd like it:
- The protagonist isn't the chosen one in the chosen mech that can just beat everyone because of how awesome it is. In fact, he's just this chump who spends the entire series in a piece of garbage practice mech and when he wins, he does so with clever planning without resorting to Code Geass levels of contrived BS.
- Surprisingly deep characters who frequently make you reevaluate what you think of them.
- Healthy blend of action, characterization, and ethical drama.
- Short and sweet (12 episodes with a second season coming in January).
Caveats:
- If you're not digging it after a couple of episodes, it's probably not for you. The character development can be kind of hit or miss.
I could keep going but I think that's a good starter list based on what I think you might like.
