What are some really good anime/manga that just aren't popular?

This list adheres to the popularity of when the anime came out rather than it's current popularity, as most anime I know now is classified as unpopular due to their age.
Habun wo Tsuki no Miteru
Iriya no Sora, UFO no Natsu
Allison to Lillia
Asatte no Houkou
Ayakashi
Bartender
Blue Drop: Tenshi-tachi no Gikyoku
Bokura ga Ita
Code-E
Shikabane Hime
Demonbane
Elemental Gelade
El Hazard: The Wanderers
Fantastic Children
Gad Guard
Glass Fleet
Haibane-Renmei
Hakushaku to Yousei
Hatenkou Yuugi (Dazzle)
Hitohira
Idol Master Xenoglossia
Jinki:Extend
Kamisama Kazoku
Key Princess Story Eternal Alice Rondo
Key the Metal Idol
Kurau Phantom Memory
Kurenai
Le Portrait de Petite Cossette
Looking up at the Half-Moon
Mokke
Mononoke (not to be confused with Princess Mononoke)
Mouryou no Hako
Mushishi
Nadia: Secret of Blue Water
Nijuu-Mensou no Musume
Noein ~to your other self~
Wagaya no Oinari-sama
Penguin Musume Heart
Pilot Candidate
Red Garden
RIN ~Daughters of Mnemosyne~
Rizelmine
Samurai Deeper Kyo
Shangri-La
Shion no Ou
Solty Rei
Sora o Miageru Shoujo no Hitomi ni Utsuru Sekai
Speed Grapher
Spiral
Tactics
Telepathy Shoujo Ran
Terra e...
Texhnolyze
The Good Witch Of The West
The Story of Saiunkoku
The Third: The Girl With the Blue Eye
The Twelve Kingdoms
This Ugly Yet Beautiful World
Tokyo Underground
Turn A Gundam
Twin Spica
Venus to Mamoru
Yoku Wakaru Gendai Mahou
Yume Tsukai
Zettai Karen Children
Zettai Shounen

Mushishi, Tokyo Underground, Spiral, Speed Grapher and Rizelmine for sure.

Unpopular, good shows that didn't catch the mainsteam's attention?

Area 88 and Sorcerous Stabber Orphen

Whoa M, you sure know your stuff ;D

I really started watching anime when I discovered that there were hidden gems beneath the mainstream. So, in a way, this was my original raison d'être when it came to anime.

sayonara zetsubo sensei? or is that semi popular?

sayonara zetsubo sensei? or is that semi popular?

Sort of. Really more cult classic than anything.

That's quite the list.

Might look into it someday =P

@M: GJ, I've only seen some of the titles in your list. 12 Kingdoms is very good, have watched it for at least 3 times.

And Kekkaishi is also very good.

Wow, I haven't been here since February...?

I saw this thread and I was going to recommend The Good Witch of the West...but M beat me to it.

I. Love. That. Manga.

But I don't even know where to read the last manga because apparently Tokyopop stopped translating it...those people don't know what they're missing.

I just finished Asatte no Houkou. It got licensed by Sentai, so I could watch it on demand. Sigh. I did like that anime a lot....

Good Witch is a pleasant surprise as it starts out as something so generic and suddenly blossoms into something quite unique without wilting interest. It needs more credit than it got.

Is Phantom: Requiem for the Phantom counted as unpopular, but a good anime?

M: Yeah. I didn't think I was going to like the main character at all (was mainly reading it for Roux/Rune or whatever) but...I don't know. The whole show just sucks you in.

But I never could find the last volume...cliffhanger ending for me I guess...

Everything else I've watched or read is more or less known. Maybe except Neo Angelique, but that show is more of a guilty pleasure to me than anything....it's not really that deep at all. But I guess this is what I've come to expect from otome game based anime...

Kamikaze Kaitou Jeanne and Full Moon Wo Sagashite