(Extra comment after posting: ...damn. This is a long list.)
Manga Published in English:
12 Days by June Kim- A sad but definitely worthwhile read about a woman living in New York who copes in an unusual way with her girlfriend's death while remembering their past relationship.
Between the Sheets by Erica Sakurazawa- about two women who are friends, but one begins to fall for the other one. I haven't read this manga yet, since it sounds like it becomes pretty wretchedly depressing.
Iono-sama Fanatics by Miyabi Fujieda- Only volume 1 was released in English. ;_; (It's still sitting alone between the Hayate x Blade and Kannazuki no Miko volumes on my shelf.) Setting that aside, the series as a whole is a fun, light comedy about Iono, the queen of a small, fictitious country, who loves women (especially women with black hair), and goes to Japan to find more sobame (ladies-in-waiting). She meets and falls in love with an OL there named Eto.
Rica'tte Kanji!? by Rica Takashima- A cute slice-of-life comedy about Rica, a young woman studying education at a women's college in Tokyo, and Miho, her girlfriend who's studying the fine arts.
Maka-Maka by Kishi Torajiro- A manga about two friends, Jun and Nene, who both attend college and have boyfriends, but still have sex with each other. I tried this one after hearing all the hype about it, but didn't care for it much.
S.S. Astro by Negi Banno- a 4-koma comedy about three high school teachers and a school nurse- Kaname, the French and English teacher, is undeniably attracted to ditzy P.E. and homeroom teacher Izumi, while uber-refined Japanese teacher Youko is a closet fujoshi, and Setsuna is the sadistic school nurse from hell. ^^
Works by Eriko Tadeno- A collection of Ladies Comics stories that all focus on adults, with one story about a woman attending her sister's wedding and considering whether to come out to her family, another story about two women in college, and a two-part story about two women who work at the same office.
Yuri Monogatari anthologies by various artists- An annual collection of yuri one-shots by Japanese and other global artists. While there are stories set in adolescence (and in one story that I can think of, childhood), YM tends to focus on adult characters.
Manga not published in English (btw, if you enjoy any of these titles via scanlation, you should really support the artist who made them by buying them so that they can continue to create good yuri- or at least yuri you enjoy):
Alice Quartet by Miyabi Fujieda- about four fashion designers (Fujieda's clothing designs are fabulous!! ^_^) who run a boutique together. The owner of the shop is in love with one of the designers.
Ameiro Kouchakan Kandan (Chatting at the Amber Teahouse) by Miyabi Fujieda- a sweet, relaxing slice-of-life series about a third-year high school student named Sarasa who falls in love with Seriho, the owner of a newly opened teahouse (the "Amber Teahouse"), and decides to work for her there. Of course, Seriho reciprocates (but realizes it later) and their teahouse gains a reputation for it's pleasant yuri atmosphere. :) In one chapter, an elderly lesbian couple also gives Seriho some romance advice.
Anise magazine- a now-defunct lesbian magazine that ran several one-shots. Luckily for those of us who don't have a copy, Lililicious is scanlating it. My favorite one-shot so far is "Song in Blue", which puts a fresh, optimistic twist on the old "my ex girlfriend's getting married" theme.
Applause by Kyouko Ariyoshi- begins in a typical prestigious Cathloic girl's school setting, but by the end of volume 1, shifts to the characters living as adults in New York. Very classic shoujo.
Aoi Hana by Takako Shimura: As I've mentioned previously here, there's a cute adult yuri couple (Hinako and Orie) among the numerous high school aged yuri characters- they begin as a minor subplot, but become (indirectly) highly influential of the main plot in volumes 4 and 5 (rather, the chapters that will become volume 5). There's also Chizu (die!!) in volume 1 and, in the "Little Women" side stories, we see that Yasuko's oldest sister Shinako also dated a girl in high school- whether that will ever come up again is another question (but hey, at least she's voiced by Mamiko Noto in the anime! ^^).
Apple Day Dream by Nene Jounouichi: Boobsboobsboobs, with a light gloss of fashion design thrown in. This 4-koma series is about two clothing shop owners, one a tsundere and one whose sole defining trait is liking women with "ZOMG!" big boobs. Charming.
Butterfly 69 by Natsuneko: A collection of one-shots. "Quilt Queen", which is about a fashion designer and a model (and the only one I've read so far) is fantastic, and it looks like at least one other one-shot, "Okujou no Kiseki", is also going to be about adults.
CANAAN by Akira Ishida: I know, I know, the yuri that I want to see in here is subtext only, ^^; and there's only one chapter out so far, but it's still an enjoyable, squeal-inducing read for me- the art isn't as appealing as it is in the anime, but it's still a title worth checking out.
Claudine by Riyoko Ikeda- A little known 1 volume manga by Ikeda, about a transgender man (a man in a woman’s body- although some people might debate whether Claudine is FtM or not) who falls in love with several women who return his affections (for a while, at least). Well-done, but it has a sad ending. (Read Honey & Honey, for a better/non-depressing story that includes FtM characters. ^^)
Clover by Hiyori Otsu- a collection of yuri one-shots about four sisters and their respective relationships in high school. The epilogue, taking place three years after the previous chapters, centers around one of the sisters when she is in law school, living with her girlfriend.
Cutey Honey A-Go-Go by Go Nagai- I haven't read this yet, but if it follows the the same general schtick as the Re Cutie Honey OAV (which it sounds like it does, complete with uber-cool Inspector Nacchan as Honey's subtext-love interest), it should be a fun action/yuri subtext read. ^^
Double House by Nanae Haruno- An under-appreciated gem; the first three chapters of this tankoubon are about Maho, a transgender woman who saves Fujiko, a rich girl who left her troubled home, from a man who harasses her. It turns out that they live in the same apartment building, and Fujiko gradually reveals that she has fallen in love with Maho.
"For You, My Beloved" by Nagi Yoshizaki and Aya Sasaki- A sweet one-shot about two women attending a nursing school in the country.
Franken Fran chapter 22 by Katsuhisa Kigitsu- This particular chapter of this wonderfully quirky horror-comedy covers a highly unusual yuri romance.
Free Soul by Yamaji Ebine- A slice-of-life drama by the consistently excellent Ebine about an aspiring mangaka named Keito who draws yuri manga while working at a record store. She falls in love with and tries to win the heart of a jazz musician named Niki.
Gunjo by Ching Nakamura- about a miserably married straight woman who asks the lesbian who is in love with her to kill her abusive husband, and they subsequently go on the lam. Yuri and introspection ensue. I haven't read this one yet, and the plot doesn't really sound like my cup of tea, but the more I read about it (and Nakamura), the more intrigued I am by how it will be. An interview with Nakamura is available here.
"Hands Off My Girl" by Minami Q-ta- A one-shot about how jealousy brings two college students together. I must admit that I’m not a fan of Minami Q-ta’s work, even though it’s...well… different, and worth checking out. (But something about her work keeps bringing me back to her stories.)
Hanjuku Joshi by Akiko Morishima- focuses on romance between two students at an all-girl's high school, but includes one adult yuri character who works as a teacher (although as a caveat, she does become involved with one of her students).
Happy-Go-Lucky Days volume 2 by Takako Shimura: Chapters 5 and 9 in this collection of one-shots by Shimura are yuri. Chapter 5 is about a woman who attends an ex-girlfriend's wedding, but meets another woman who also used to date the same woman. Chapter 9 (my favorite of the two) is about a woman who falls in love with her roommate.
Haru Natsu Aki Fuyu (Spring Summer Fall Winter) by Zaou Taishi and Eiki Eiki- three chapters of this volume (titled "First Kiss") are dedicated to the romance between a school nurse and teacher who work at the same school; during other parts of the volume, the school nurse gives romance advice to one of the students.
Honey & Honey by Sachiko Takeuchi: a manga that was primarily written to explain lesbian relationships to a straight female audience, following the lives of Sachiko, a college student, and her girlfriend Masako, along with other people in their lives. An interview with Sachiko Takeuchi can be found here at Tokyo Wrestling, a Japanese lesbian media site (like a Japanese Afterellen) that translates its articles into English and French.
"Interface" by Ken Kurogane- A fairly unique one-shot from issue 1 of Yuri Hime S, about a high school student who meets a girl who draws a figure on a board using a pendant, and then says that the pendant is "her" and gives it to the protagonist. The protagonist tries to find out who the girl is over the course of the story, and an adult yuri character shows up later on who explains everything.
Indigo Blue by Yamaji Ebine- A writer named Rutsu is dating her editor, Ryuuji, but she meets a woman named Tamaki who she begins to fall for, causing her to question her sexual identity. One of Ebine's earlier yuri manga and, like the rest of them, highly recommended. Interestingly, Ebine commented in her interview with Tokyo Wrestling that this title seems to be a hit with women in their 30's. ^^;
"Instinct and a Chromosome" by Haruko Okai and Maiko Akiyama: A one-shot about a woman attending business school and the woman who she falls in love with there, along with the obstacles they face before they can have a happy (?) ending. I didn't care for this title much, quite honestly, although it's worth checking out for fans of josei yuri.
Junsui Adolescence (Pure Water Adolescence) by Kowo Kazuma- a romance between a high school student and a school nurse; one of the other teachers shows some interest in the nurse, and remembers when she herself fell in love with a teacher when she was in high school. In the fine tradition of candy-coated shoujo romances, Junsui Adolescence manages to make a romance that would be...well...illegal and damaging in reality, seem kind of cute and inoffensive. -_-;
Kawaii Anata (Your Cuteness) by Hiyori Otsu- A collection of one-shots, my favorite being “Maple Love”, which is about how two college students (a cynical pragmatist and an airheaded romantic) become a couple.
Kiseki Goten by Wako- A tankoubon collection of stories that ran in the Ladies Comic magazine Mist, about several women who solve their problems through the Kiseki Goten, which sounds like a glorified hostess club for women. ^^; OOP, but on the Planned Projects list for Lililicious.
Kotonoha no Miko to Kotodama no Majyo to (The Miko's Words and the Witch's Incantations) by Miyabi Fujieda- about a witch (Letty) who frees a miko (Tsumugi) from the shrine that she was entrapped in as a child and shows her the outside world- and of course, they fall in love. ^_^ The miko's protective female bodyguard has a crush on her also. This might be my favorite manga by Fujieda.
Kurogane Pukapuka Tai by Shinsuke Kurihashi- If you're going to read one yuri WWII parody gag manga, make it this one! ^^ It's vaguely similar to Hetalia (and similarly, not terribly remarkable), but it has women and yuri and combat...and it's better, coincidentally. It's entertaining enough- and quite honestly, it doesn't offend my sensibilities remotely as much as Hetalia does. My favorite character's the uber-protective lovestruck swordswoman/Executive Officer Mamiya. ^^ (But...goodness, what does she see in Commander Kuki?) For added interest, one of the characters is named "Obama." :)
Kyoshiro to Towa no Sora by Kaishaku- Unofficially dubbed "Kaon to Himiko no Sora" on the ShoujoAi.com forum, because that's all that most of us yuri fans paid attention to this series for. ^^; Kannazuki no Miko's Chikane and Himeko reappear as a side couple, this time named Kaon and Himiko, but the EPL headmistress of the school they belong to who controls Kaon tries (unsuccessfully! ^^ bwahaha) to thwart their love.
Linkage by Uso Kurata- A collection of stories from Yuri Hime and Yuri Hime S. The only one-shot in it that I absolutely know includes adult characters is "Kusari wa Mou Iranai",
a wonderful office romance that ran in issue 6 of Yuri Hime S. ^^
Love My Life by Yamaji Ebine- Another slice-of-life drama (and Ebine's best manga, imo) about Ichiko, a college student who comes out to her dad, which causes him to tell her that he's gay, as well as her (now deceased) mother. Ichiko has a girlfriend named Eri, another student who's studying to become a lawyer.
Love Slave by Kahori Onozucca: I haven't finished reading this one. It's another "woman who's dating/married to a man meets a lesbian she knew in high school and leaves her boyfriend/husband for her" story, but with a darker slant. I like how the protagonist, Ureha, seems more outspoken and assertive from the outset than most protagonists in this sort of story (not the timid princess who needs to be rescued), and her new girlfriend, Kahori, is far from the "knight-in-shining-armor" personality that I would expect from someone in her role. I don't really like Kahori and think that Ureha could definitely do better, but for now I'm really curious about how the story's going to end.
Love Vibes by Erica Sakurazawa- The protagonist, Mako, is a college student (admittedly, one who doesn't seem to take her studies very seriously) who finds love with Mika, another young woman around her age. This story is very well-done, although I can't say that I really like any of the characters much. <--Same note added to the "college-aged" list: Wtf. No. Read this.
Magical War Chronicle Lyrical Nanoha Force by Masaki Tsuzuki and Yukari Higa- The fourth season of Nanoha, which began serialization in Kadokawa Shoten's Nyantype (-_-; ...) bishoujo magazine in April 2009. Nanoha and Fate are both 25 in this series, and hopefully (?) there will be some subtext here a la StrikerS- although judging from the picture above and a glance through the first two chapters, it looks like the focus will be on a new character (the generic-looking guy waving a blade in the foreground of the picture above). Here are a couple of StrikerS Nanoha/Fate pics, regardless:
Mermaid Line by Renjuurou Kindaichi- A collection of Yuri Hime stories about three unrelated couples. The "Yukari and Mayuko" one-shot (about two OLs) irritated me on multiple levels, but the two part "Ayumi and Aika" story- about a woman named Ayumi whose boyfriend Ryuunosuke tells her that he's a transgender woman (who changes her name to Aika), and they stay together after she realizes that she still loves Aika- was the gem of this book.
Moonlight Flowers by Mutsumi Tsukumo- A lovely, classic old school yuri manga about a woman named Sahoko who is about to marry a man who she met through an omiai, but reconnects with Kaoru, a woman who once loved her in high school and still harbors feelings for her. (My inner cynic says: "Holding onto feelings for somebody who rejected you in high school for that long would normally be...kind of unhealthy." My inner romantic replies: "Shut up. -_-; This is old school shoujo- and Tsukumo makes it work. ^^") The second part of the book is about Kaoru realizing her sexual identity in college after seeing two other women form a relationship.
Octave by Haru Akiyama- An ongoing multi-volume series about an assistant manager working at a talent agency and a song composer (both former idols) who fall in love. A sometimes frustrating, but damnably addictive read.
Otome Kikan Gretel (Maiden Organization Gretel) by Kaoru Sudoo- In Chapter 6, it's indicated that two of the teachers, Rosa-sensei and Shastriya-sensei, like each *other*. Shocking, I know- teachers who don't date their students. o_o;
Otome-iro Stay Tune by Miyabi Fujieda- another cute love-comedy from Fujieda that chiefly focuses on romance between two seiyuu who voice characters in a yuri radio drama, with a few other adult yuri characters thrown into the mix.
Papaya Gundan by Mitsue Aoki- about a group of people/friends who work at and run a hostess club. Two of the hostesses fall in love with one another. I haven't read this one yet, but I'm looking forward to reading it since the reviews have been really good.
Phryne magazine- Another defunct lesbian magazine (yeesh) that also published several one-shots about adults. For those of us who can't get a hold of this long OOP magazine, Lililicious is kindly scanlating it.
Pieta by Nanae Haruno- Another excellent title by Haruno. ^^ It seems to be another all-girls' high school story in the beginning (albeit, with an unusually mature sensibility) but develops into much, much more- intertwining themes of family drama, psychological issues, the journey to carve out one's identity, and romance into one addictive yuri manga. (Thanks goes to Nakayo for recommending this!)
Plica by Sae Amamiya- a series of webcomics about the daily life of Plica, a young woman in the workforce, her girlfriend Mari, and a few other yuri characters.
Poor Poor Lips by Hayako Goto: A 4-koma about a poor young woman named Nako who applies to work at a jewelry store owned by Ren, an openly self-identified lesbian.
Rakuen no Jouken (The Conditions For Paradise) by Akiko Morishima- features a three chapter romance between an office worker and her long time best friend who works as a traveling freelance writer, as well as stories about other adult yuri couples.
Reijin na Hito (Beautiful Woman) by Takumi Kobayashi- About a woman who helps women solve their problems by sleeping with them (^^; ...?), but rediscovers the woman who she really loves in the end. Another OOP Mist collection that Lililicious is planning to scanlate.
Rose of Versailles by Riyoko Ikeda- About a French noblewoman named Oscar Francois De Jarjeyes who was raised as a man, and serves as the Captain of the Guard at Versailles under Marie Antoinette. Many women at the court seem quite taken with Oscar's competence and androgynous good looks, and Oscar and a woman from the lower class, Rosalie, develop feelings for each other but don't end up together. A must read for manga and yuri fans.
Ruriiro no Yume (Lapis Lazuli Dream) by Akiko Morshima- Morishima's second highly-anticipated collection of Yuri Hime one-shots, which will feature a bevy of adult yuri characters (yay! ^^)- including Hanjuku Joshi protagonist Chitose's older sister Chie in the otaku love-comedy, "Soft-Boiled Fujoshi."
Strawberry Shake Sweet by Shizuru Hayashiya- Aside from our central baka-couple, Julia and Ran, and younger idol Haruna, every other female character in the core cast of SSS, yuri or not, is an adult- my definite favorite among them being Ryou from the all-lesbian visual kei group (that was fun to type) Zlay! ^_^
"Sweet Exercise" by Amano Shuninta- A one-shot in issue 3 of Yuri Hime Wildrose, which was brought to my attention for having college-aged characters; it hasn't been scanlated yet, but it should be out soon. The Wildrose anthologies have some other one-shots with adults as well, although they largely seem to focus on high schoolers. :(
Sweet Lovin' Baby by Yamaji Ebine- A collection of one-shots by Ebine that include several adult yuri characters. Highly recommended.
Tokimeki Mononoke Jougakuen (Heart-Pounding Excitement at Mononoke Girls' Academy) by Banana Nangoku: In this amusingly eccentric yuri comedy set at an all-girls' school for youkai, one minor subplot involves one of the teachers, Rokurokubi-sensei (a youkai with an extra long neck) secretly dating one of her students, a snow woman.
"Traces of Snow" by Mako Takahashi: A one-shot in issue 1 of Sayuri-hime (a special mini-edition of Yuri Hime magazine) about a woman who receives a visit from a friend she once was (and probably still is) in love with.
Transistor Venus by Izumi Takemoto- A fun, refreshingly different futuristic sci-fi series about a spy named Enus who lives in the year 2269. It's multiple volumes, too! ^^
UFO Ultramaiden Valkyrie volume 7 by Kaishaku- In this otherwise unremarkable volume, Chikane and Himeko show up (once again, with new names; see the top-right corner of the picture above :) ) as the owners of a ryokan that the protagonists of this series vacation at.
"V Hunter" by Shizuru Hayashiya- A cracktastic yuri comedy one-shot about a girl who unwittingly rents a demonic video tape, and the
Wagamama Juliet (Selfish Juliet) by Shuko Iizuka- a woman who knows that she is gay, but doesn't know anybody else who is, decides to marry a man, but shortly before her wedding she meets her first love from junior high. Even though the plot superficially seems similar to Moonlight Flowers, it actually has some significant differences (from what I've read about it). It's another old OOP manga, ;_; but once again Lililicious is coming to the rescue! ^^
Yozora no Ouji to Asayake no Hime (The Prince of the Night Sky and the Princess of the Morning Glow) by Mera Hakamada- A collection of one-shots. One of the stories, "A Love Song in a Nameless Country", is about a princess and the ninja who serves her. The story is really cute (until...that ending T__T), but I don't care much for Hakamada's art.
Once again, suggestions for any more titles are welcome! ^^