From Day of the River:

A doting father finds out that his precious daughter has found herself a boyfriend. For any father, this news alone is hard enough to accept. However, when the boyfriend turns out to be a potential lying playboy, this father will stop at nothing to protect his little girl!

A plain but considerate main character falls for a girl who happens to sit next to him in class. Using a group project as an excuse, he gets her number and they go on a date, but everything is ruined because of the unexpected rain and his credit card reaching its limit. Over the course of the story, the main character learns the hardships of love. Original Webcomic

In the Mirai no Kioku series:

V.1 - Mirai no Kioku

V.2 - Kaze no Yukue

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From Deux Press:
Kento Kumagaya wishes for just one simple thing: to have a happy family with the ideal housewife, loving kids, and kind grandparents all living together, happily ever after. Life, however, has other plans. Enter Akira Kazuki, a smart, beautiful and unrestrained gay man who shatters Kento’s dream with a single night of wild and passionate homosexual sex. This is a romantic, sweet and funny story between two different people (in more ways than one) who unexpectedly find the same future together.

Note: also contains an unrelated oneshot called "Winter Rabbit" in the English release by Deux Press.

Tsugawa Tatsuya just lost his parents in an accident... but he's trying not to let that keep him too down as he starts high school.

While trying to obey his father's final wish for him to become an upstanding man, he ends up helping a girl who was being bullied. Despite her exceedingly cold nature, he just can't leave her alone... which may not necessarily be to his benefit, as he ends up getting wrapped up in a world where things like parasitic mind-controlling bugs exist...

There's a reason why I help clean the school swimming pool. And the reason is a bit sentimental.

From Anime Waves:
Rena Misaki was a normal girl in high school in the small town of Otogi. But lately she is being tormented by Kegari Chota (little hamster like imps that cause greatly increased sexual desire). They had been banished from the village long ago by a priest. But somehow they have returned and have taken an interest in Rena. And if that wasn't enough trouble, they are starting to spread. Rena has to find away to get rid of them and have a normal life, before she ends up sleeping with all the guys around her.

The story of Yukako Kamoto, an Instant Curry lover.

From Viz:
At first glance, Nina Sakura seems like a typical teenage girl. However, she's actually a transfer student from a witch school! Now enrolled in a Japanese middle school, Nina is hoping to improve her grades, make some friends, and practice love spells on her unsuspecting new classmates.

Shy Ayu Tateishi has just made a new friend at school. But this new friend, much to her surprise, is no ordinary classmate. Nina Sakura may look like a normal middle school girl, but she's got a big secret.
She's a witch.
Or, rather, she's studying to be a witch. And apparently, she's not doing her homework. Her spells are devastating in their ineffectiveness and often result in the most embarrassing situations for poor Ayu.
But things wouldn't be so bad if Nina's sorcery didn't make Ayu look silly in front of the one boy she secretly adores. All she wants is a simple love potion. What she gets, however, is a new best friend who almost flunked out of witch school!

From Viz:
All high school freshman Airi Hoshina ever wanted was to someday live in a cozy home with a loving husband, and find joy in the little things in life. As a result, she makes it her daily mission to get to school on time because school legend has it that the longer one's non-tardy streak is, the better boyfriend one will find. But just when her daily routine is working like clockwork, an occurrence of fairytale proportions threatens to disrupt her grand plan.

All Miki Koishikawa wanted was an ordinary family and that's exactly what she had until her parents decided to move in with another couple (as in switching spouses!) and turned Miki's world upside down. Now she lives in a house with four parents and her totally cute stepbrother, Yuu. It's bad enough being brought into her parents' strange soap opera, but Miki will star in a soap of her own as she deals with friends having affairs, trying to survive in school and ending up torn between her long-time crush, Ginta, and her new stepbrother!

Keitaro has had great difficulty getting into the university of his choice and no luck in meeting women. In a desperate effort to go into seclusion and study for his entrance exams, he volunteers to take over running his grandmother's hotel. His plans are ruined when he discovers that the "hotel" is actually an all-girls dormitory and some serious distractions ensue.

Note: Won the 25th Kodansha Manga Award for Best Shounen in 2001.

Yusuke Urameshi was a tough teen delinquent until one selfless act changed his life... by ending it. When he died saving a little kid from a speeding car, the afterlife didn't know what to do with him, so it gave him a second chance at life. Now, Yusuke is a ghost with a mission, performing good deeds at the behest of Botan, the ferrywoman of the River Styx, and Koenma, the pacifier-sucking judge of the dead.

Note: Won the Shogakukan Manga Award for shounen in 1993.

"Koganeiro" is about a group of high schoolers in their second year who are confronted with the possibly life-altering decision of what to do after high school.

Satou Hiroshi is the kind of polite, innocent, cute boy who's popular with guys and girls alike. But word-of-mouth has it that anyone who dates him will be plagued by a series of unfortunate events and near-death experiences - eventually being forced to institute a break-up 'under pain of death'...

Will bespectacled, 'uncool', baseball-crazy Tsumabuki Kasumi prove these rumours wrong or experience them first-hand? But after falling for Hiroshi's cute smile upon their (rather weird) first meeting, he's determined to tempt fate and find out whether he can finally break out of this unlucky streak and strike it lucky in his love life!

Fall from a building, fall in love.
Shinji was a high-school guy without a future.
He went up to the roof of a building with plans to jump, only to run into his beautiful teacher, Shinanoya-sensei!
Then she made a shocking proposal that would change Shinji's destiny...
An exuberant tale of double suicide from the pen of a genius!!

Friendship blossoming to love between a high school girl who tries extra hard to make up for her lack of height and a middle school boy who just looks too tall to be his real age.

This is a Thai comic.

Han Se In finds street fighter Moon Ji Soo on the street. When she tries to help him, he tells her to go away. Se In wants an apology but Ji Soo won't give one. She then slaps him and runs. Moon Ji Soo wants revenge...

From 1st Chapter:

The lead character is a naive boy who's fallen in love with an older girl who everyone considers a genius writer. He's so in love in fact, that he has forgotten for the last 2 months about his secret hobby. For the past 10 years he has been writing the "character profile" of a single girl. Her birth date, personality, hobbies, conversations, etc.... is all recorded in a large pile of notebooks. All this time this fictional girl has been his friend and lover, but now that he is in love with a real girl he decided to throw them all away.

In order to "purify" the notebooks, he decided to burn them at a nearby shrine. To his surprise, the senpai he's in love with was also there. It starts to rain and as they talk the girl confesses she's having trouble writing her novel due to inexperience. As the storm gets even stronger, the lead character believes that since she confessed her "weakness" to him it is OK for him to show her his own "secret". Filled with courage, the boy opens the bag where he brought all the notebooks... except that instead of notebooks, the bag now contains the girl (naked of course) he's been creating for the past 10 years!!

From Nakama:

A strange household made up of two divorced fathers with a child each. As the children get older, they start to become aware of the strangeness of their own household…?! Following the popular BL about fathers with children, “Kodzure Ookami”, the children become the main characters as we follow their growth, in this long-awaited next volume! Also, a straight-laced tax counselor who is also an idol otaku, and a show pub owner of questionable identity (only half Japanese and also an onee); their fateful meeting and subsequent circumstances. This is the well worth-reading 3rd compilation in the series of this author.