I'd nominate Darker than Black. Although it's 2nd season wasn't seen as a huge success, I think plot wise it still provides a good setup for a potential 3rd season. It seems like they were even planning on one, but it got put on the back burner/cancelled.
What do you guys think?
Ryuugajou Nanana no Maizoukin (Nanana Ryuugajou's Treasures) because why not ? Just kidding.
I highly demand a second season for this because there's a lot of things that haven't been explained and a lot of things that needs to be shown. Like, who are all the Great 7 and how was Nanana murdered in that room. And of course, MORE TREASURE HUNTING !!!
The thread "Anime that really need a sequel" and its comments have been merged into this thread.
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Pretty self explanatory, I call upon Hataraku Maou-Sama!, that anime really needs a sequel, what do you guys think needs a sequel?
I'd give out some :
Guin Saga
The anime barely scratches the surface of this epic series.
Glass Mask
The anime was just getting to the best part when it ended. Although the manga is slowly getting translated, I much prefer the character designs in the anime.
Zipang
There are still 36 volumes that could be adapted. Sadly, the manga is not getting translated. I want more of this time-travel thriller!
Five Star Stories
The anime only covers the first volume of the manga. People who only watch the anime have no idea how grand the story is. It would make one epic anime series.
I really wish we could have gotten a second season of Darker than Black.
And at least we got a movie for Psycho-Pass, but a second season would have been really cool, too.
[Removed]

WHERE is the "joke?" Posting BLATANTLY false information, knowing SOMEONE will take it at face-value (for YOUR sake) & then "calling" them on it qualifies as a "joke?"
It's not posting blatantly false information in hopes that someone will call me on it. It's denying the existence of something as a way to say "this was really, really bad and I'm going to pretend it doesn't exist."
But the real joke here is how you have no idea how to use caps lock or quotation marks properly and have instead invented your own style guide, making you look like a tool and a complete idiot to anyone who reads anything you write.
You should DISCONTINUE that kind of "joke," it is NOT HELPFUL. @origamimissile probably thought that YOU GENUINELY THOUGHT that DARKER THAN BLACK and PSYCHO-PASS had only one season - - - he was being HELPFUL.
For future reference: SNARKY comments should be denoted by ITALICS.
Post Scriptum: COOL DOWN.
Spice and Wolf could use 1000000000 more sequels.
I'd love to see more of Toradora!
And Servant x Service could use one too.
No Game No Life because they teased the shit out of us on the last episode. The anime would be incomplete w/o a second season.
And Trinity Seven. I don't even like it plot-wise but plot-wise, it was enjoyable. Also ya the mc hasn't completed his goal yet either. I just want more of its great art style, music, and tits.
Edit: There's always this thread you know
I would love to see more Toradora! and Bunny Drop . Those are probably the two I really want. The third would have been Saekano but that's already happening so Yea! :D
HMS are probably the series whose sequel I would most appreciate as well. From the series I've rated with a 7 or higher, I also wouldn't mind some more Baccano. If there are some that would require a sequel to conclude the issues they've brought up in the end, whether I personally liked them or not, it would be Haganai Next and Kannagi from what I've seen.
That said, I prefer new settings over continuations of previous ones, no matter how good they are. So, I'm way more for some good new series over sequels of previous good ones.
I think I would really like it if they had a sequel to...
White Album 2
No Game No Life
Witchcraft Works
Black Bullet
Mekakucity Actors
The Devil Is a Part-Timer
The Comic Artist and His Assistants
One Week Friends
Trinity 7
I also wish that they would continue Katekyo Hitman Reborn, as well as Magi... :(
Dungeon ni Deai wo Motomeru & Ben-To

Danmachi is confirmed to have a second season.
Seriously? WHERE? LINK?
Its not out yet, its just confirmed.
Obviously, but where is the link showing that it has been confirmed?
No Idea, haven't seen it myself, but it is widely said that its gonna be made 2017.
Just my personal opinion. I'm not gonna rank them though. I don't think HxH or MK1412 will get a sequel in a LONG time. I doubt Maou-sama is gonna get one either, and about a bajillion people have already told me that No Game No Life will never get a second season which is really disappointing.
I do think that GSNK will get a season 2 (I really hope that it gets a season 2, because it's honestly one of the funniest anime's I've seen in my life. Maou-sama and GSNK rank the same on the funniest ones.) and I also think that Yona might get a season 2 and I really hope it does. I think maybe Yamada-kun might get one as well? It didn't get bad ratings, and it was really good in my opinion. I need Shiraishi back, and the opening was sweet.
Totally agree that Hataraku Maou-Sama!, No Game No Life and Dungeon ni Deai wo Motomeru should have sequels but I would also like to see more of Toaru Kagaku no Railgun, though it is a two season series and it has a parent anime also with 2 seasons.
Oh! and I would love to see a second season of Shirobako
I'd love to see another Full Metal Panic!. I know that they have enough novel content to make it happen, so it'd be a nice surprise.
I second wanting a sequel to MM! One of the few ecchi shows I enjoyed, cause of it's humor, characters and story.
We need a Hataraku Maou-Sama! second season too.
Apart from that, a sequel to:
Seikai no Senki III - I really need them to adapt the 4th and 5th light novel.
Akatuski no Yona - I am still waiting for my S2, make it happen.
Gekkan Shoujo Nozaki-kun
Shirobako - I am in the middle of watching this, but I am pretty sure I would want more after I finish it.
I haven't seen it mentioned, but Chihayafuru needs a 3rd season, I would be really sad if it doesn't get a 3rd season actualy, everything was pretty cool in this anime and it litteraly didn't ended ! (I think this anime was quite popular too ...)
Hey, where is Elfen Lied?
Well, Elfen Lied is lacking a presence here simply because it's 11 years old. But aside from that entirely, I think it goes without saying that it had a beautifully-scripted ending, and its impact would only be diminished if the series were to receive an extension.
It truly was open to interpretation done right.
Well, I know what you mean, but: why to be so cold? I don't know how to feel about "open to interpretation". It's a love-hate relation xD
Elfen Lied spoilers follow
The music box was tied to Lucy. This connection was made very strong through the use of flashbacks. The grandfather clock was tied to Nyuu, as it was the one thing she was often seen tinkering with while staying at Kouta's house; also worth a mention that it was broken until the very end. The sudden stop of the music box represented the death of Lucy (who'd recently "shed her horns" in the firefight), and the chiming of the clock represented the birth (and sustained life) of Nyuu. Who is seen standing at the gate in the last few seconds? No one other than Nyuu. It was all open for speculation, but the symbolism directs us to a rather definite--and positive--conclusion. This is why I love it so.