Sugiyama Rika is the Chief of Public Moral in her school and dislikes the school's student body President Jinguuji Kasui. She thinks he's incompetent and an expert at lying. One day a rumor broke out about a myth about love in their old school building, suddenly Rika finds herself entangled in the love myth with none other than... Jinguuji Kasui?!

From Chibi Manga:
Loved by a handsome little problematic brother...

He is blunt, but a kind brother, Haruka. a sister who's very close to him, Setoka. But, one day, Haruka's secret is leaked out ----!?

A unbelievable love story with a handsome brother, start!!

She was her best friend and he was her first love... she didn't plan to change that. Ayu and Kaho were friends since kindergarten. They were the exact opposite and even if both them were cute, they hated men. But one day, Kaho found someone she loved. (Source: Chibi Manga)Included one-shots: ...Suki.; Zutto Zutto Daisuki

At 17 years old, I didn't know anything about life or love and I wasn't seeing my cousin as a "man".I'd like to not know anything at all but love changed everything...
(Source: Chibi Manga)

Story 1: Sayonara Demo Aishiteru - Yutaka's version
Yutaka has decided to confess to Mariya, the girl who saved him during the entrance examination. Being an average girl, Mariya was bewildered by the confession of the charming Yutaka. Even though there are strains in their relationship, the distance between the two slowly shortens. However, Mariya has suddenly asked for a breakup!
Story 2: Sayonara Demo Aishiteru - Mariya's version
Story 3: 1% No Kiseki
Story 4: Sumetaku, Amaku, Koi O Shite
(Source: Midnight Scans)

"All girls can become cute"
What a lie… thinks Yuni. That Yuni could change like this is because of the new brothers she got through her father's second marriage, Yamato and Hiroto, who persuaded her to perform in an audition.
But Hiroto confesses to Yuni, who formerly got bullied for her "squish-face", so she's determined to become cute! What will be the conclusion for love and the audition?!
Source: Chibi Manga

From Midnight Scans:

1-3. Kareshi Toshishitakei
Her childhood friend, Sou, returns from America for the first time in five years. Ai is really happy to see that he has become very angelic looking in the time that they've been apart. However, one day he says, "I will definitely make Ai mine", and forcibly kisses her! To get treated like that by someone three years younger than her and who she's always treated as a younger brother takes Ai by surprise. It would definitely make Ai's heart skip a beat, wouldn't it?!

4. Gyakuten Valentine

5. Kimi ga Hajimete

It's been half a year since school started, but she still isn't able to get a boyfriend. While she was walking on the streets late at night because she had to work late, she suddenly started wishing that she had a boyfriend. And a devil appeared in front of her eyes!? The guy who jumped in front of her on his skateboard looked like he had black wings...! He had jet black pupils and hair with a handsome face. And without notice he suddenly kissed her...!?

My name is Takahashi Akane. I found a good boyfriend. His name is Kurotsuki Yuito. But he lies like a fox. but...isn't lies the beginning of love?!
(Source: Chibi Manga)

The moody, picturesque him. The puppy-like me who wants to express my love. I wonder if we can grasp this love well.

(Source: Chibi Manga)

From Chibi Manga:

Wakaba has no memories about her first lovea€| The only thing she keeps from her first love is a matching pendant. One day, the vampire of rumors, Yukito, comes to her school. And he has the same pendant as her?!
Wakaba is sure that Yukito is her first love just after telling him, he kissed her.
But why is he so cold with her after that?!

Besides there are two other side stories:
Un Chocoholic
Bloody Honey