Yo

So I consider myself a pretty big anime fan. I mean for goodness sake I have my OWN ChrunchyRoll account. That's big time. 

But anyway, 2 animes that I've recently finished; K (K Project, 13 episodes) and Gargantia on the Vendurous Planet (also 13 episodes) really impressed me. Both sucked me into that universe with such a small amount of episodes. Plus I was able to binge watch them in a day or two because I obviously have no life. 

Got me thinkin', anybody know why other "1 season animes" that are good and they'd recommend? 

Edit: so it doesn't have to be exactly 13 episodes. It could be 5. Or 10. Or 25. Usually 25 would be a max though. 

By 1 season I mean the entire series concludes in 1 season. 

Series I've seen already: K, Gargantia, Fate Zero, Madoka Magica, Akame Ga Kill, Kill La Kill, Pokemon Orgins

Kill la Kill - 26 episodes

Puella Magi Madoka Magica - 13 episodes

Both of those animes were amazing. Try Angel Beats, it's around 13 episodes.

"1 season only" you say.....I guess you don't want Steins;Gate then, or Bebop.

Geez I'm so out of touch with most of the current day stuff. :D

But I watched Another about a year or so ago and found it pretty enjoyable (which is rare for me nowadays) so maybe that's something people can check out(if it's not super popular and everybody has seen it already, I really have no idea.).

I assume you're primarily looking for anime that actually concludes in 13 episodes, and doesn't simply end without getting a second season.

Death Parade
Baccano
Plastic Memories
Rage of Bahamut: Genesis

And that's all I've got off the top of my head. I've watched way more 13 episode anime that just ends too soon than I have that's actually capable of wrapping up a complete story in a 13 episode season.

watching Movie 3 of Puella is a must (imo), so i don't think it complies with the OP. Stopping after the 13 ep is criminal, even if it's a "proper ending".
An alternative would be to just watch the 3 movies instead, it's basically the length of 12-13 eps and it covers the whole story

I dont know if you're into slice of life but here are my favorites. (some of them might not be on crunchy roll)

AnoHana

Beck (Mongolian Chop Squad)

Shiki

Angel beats

Welcome to the NHK

Your Lie In April

My Love Story!!

Is It Wrong to Try to Pick Up Girls in a Dungeon?

Shingeki no Bahamut

And, uh, I don't know. The best anime is usually two seasons long.

The only anime I've watched that had only 12 episodes was Majimoji Rurumo, such a shame that it was so short, I liked it. But some good animes that I liked that had 24/25 eps were Steins;Gate (Must watch!), Haruhi and Nanatsu no Taizai.