Underrated/Unknown Animes

You've asked the right person! I like to watch underrated animes too! xD

Morita-san wa Mikuchi (although this one is short)
Tantei Opera Milky Holmes (it has a bit of sexual themes or whatever though)
AnoHana (it has gotten fairly known though :)
Hanayamata
Shigofumi
Gosick (haven't watched it but from what i've heard it's pretty good)
Saki: Achiga-hen (the original/other Saki had a bit of Yuri so here's a more grounded one)
Myself;Yourself
Kill me Baby (it's pretty weird,but it's fairly good)
You and Me
Sora no Woto
Kokoro Connect
Arcana Famiglia (maybe?)
Inari Kon Kon (i recently watched this,it's short too)
hmm...maybe Azumanga Daioh or Little Busters,but personally i think they're pretty well known? i dunno

sket dance and some of the series i would like to mention is mentioned by alinah

and even chihayafuru :)

Kino's journey
Ikoku meiro no croisee
tokyo magnitude 8.0
Tsuritama
tegami bachi
gunslinger girl?? (idk is respected but i consider it underrated because no one really talks about it)
earl and fairy

Here's Mine:
1.Medaka Box
2.Katanagatari

I Really Love These Anime's And I Think It's A Shame That Most People Don't Give Them Any Attention !!!!

Alpen Rose
Les Misérables:Shōjo Cosette
Prétear
Magic Knight Rayearth(I wouldn't call it unknown but it is pretty underrated in my opinion,)