Nanoha and Chidori are best friends. They're also dating, but it's a secret, so don't tell anyone!

From MangaHelpers:
Nogawa Izumi is a good student, and a class representative, but she has an increasingly high libido. It's gotten to the point that she'll claim to feel bad during class, so she can run to the nurse's office and masturbate. When she learns that the Earth is being invaded by aliens that look like people dressed up as animals, it turns out her high sex drive may be able to help protect the Earth. The first time Izumi is attacked by the aliens, she is rescued by Usayama, a bunny alien whose race was their previous victim. Usayama gives her a swimsuit that will allow her to fight the aliens, but which also sends her constant arousal through the roof. The scientific organization that Usayama is affiliated with think that Izumi, with her high erotic level, may be the person they've been looking for to fight the aliens. Will Izumi be able to save the Earth?

Ayano, an elementary school teacher, stops by a bar that she has not been to in a while, where she meets another woman. The two get along well, …for now that is? Within Ayano is a secret she’s not really ready to disclose, what will happen then?

Asumi-chan uses a lesbian brothel to try to find her childhood friend.

The everyday lives, games and hijinks of high-school girls at an all-girls school.

Nagisa Ootsuki shed her former self out of shame from failing her highschool entrance exams. On her first day in her new highschool, who does she meet but the girl who made her fail the exam! How does Nagisa deal with these complicated emotions?

Author's twitter: https://twitter.com/sakuragi_ren

Sequel series to: Asagao to Kase-san

High school girl Hinako is living a quiet life in a seaside town, but she feels somewhat detached from her friends during the summer months when she is reminded of when her family died years ago. One day, she meets Shiori, a mysterious girl who reminds her of the ocean, especially when it comes to her translucent blue eyes, but Shiori soon reveals that she is actually a mermaid who has been looking for Hinako for a long time.

Links:
Author's twitter: https://mobile.twitter.com/naekawa_sai

Our ages are different, our ways of life are different, everything is different. But...I just want to be with her.
Because I've never been in a miserable, tragic romance, I can say that unrequited love is fine.
I don't know why I fell in love with this person...it's a mystery.

They have different personalities, different ages, different ways of thinking, different looks, different everything.

This is the story of girls who clumsily make up for what's lacking in the other.

These are new side stories. Not a rewrite of the original serialized twitter comic.

Kisshioin Tsubaki aka the "Crimson Camellia", a beautiful lady reporter of the occult, wants to satisfy her intellectual curiosity by having a hands-on experience with every Yokai she can find.
Follow her in her travels, accompanied by her trusted cameraman Yokomizo-kun.

Himari fell in love with the band and Sakura at the new student welcome party when the band performed.
Himari talked to Sakura, and she fell in love with her smile.

Somebody wants the Earth! After being invaded for 6 times by monsters and aliens, Tokyo was damaged and almost destroyed. When Runna Minami meets an honor student, Mika Kujiraoka, the bishojo fighters of justice, Mikarun X, are born.
They transform themselves into giants and, without wearing anything, the two heroines fight against the various enemies.

A story of two close friends living together.

Highschool teacher Saeki Nao is secretly a hardcore otaku who loves yuri manga.
One day, at a doujinshi convention they participate in, Nao is eager to convey her feelings to "Nyapoleon", an artist she worships.
However, it turned out to be a girl from her school, Kurumizawa Haruka, and moreover, she had to help her.
After the event, they decided to go out for a meal, at Haruka's suggestion....
When she wakes up in the morning, there is Haruka in the bed...?!

In an attempt to win her homeroom teacher's heart, Itsumi Toudou purchashed a shady love potion, and tested it out on her stuck-up student committee president, Yomotsuka. Now, she has an uncharacteristically affectionate girl to deal with, and she's not even a lesbian! Right?

Ordinary office worker Oohashi Rei wakes up in the body of the protagonist of her favorite otome game, Revolution. To her delight, the first person to greet her is also her favorite character, Claire Francois–the main antagonist of the story! Now, Rei is determined to romance Claire instead of the game’s male leads. But how will her villainous lady love react to this new courtship?!

Links:
Author's Twitter: https://twitter.com/inori_narou - Tweets in English, Japanese, and Korean.
Artist's Twitter: https://twitter.com/aonoesu - Tweets only in Japanese.
Official English Novel: https://sevenseasentertainment.com/series/im-in-love-with-the-villainess-light-novel/

In a world where animal people and humans cohabit with each other, Chief Constable Alice Sherlock is just a cowardly police officer. But one day, a strange turn event roped her into a robbery that is far more complex than it first seemed.

Kamiina Botan is a 20-year-old college student.
At the welcome party for the dorm she was assigned to, the dorm leader Ibuki gives her a highball to drink and she becomes tipsy, leading to her involvement with Ibuki from now on...
A tipsy teasing girl's comedy!

Official Manga Twitter: @Kamiina Botan: https://twitter.com/kamiinabotan

Mangaka's Twitter: @Hey 塀 : https://twitter.com/tonarinohey

This is the story of Misora Haebaru, an 18 year old karate expert from Okinawa who went to Tokyo to enter the entertainment industry in hopes of supporting her family. She gets tricked into being a gravure idol who wears lewd clothing and is forced eventually to enter the AV world, but she wont go down without a fight.

Two sisters, with ten years separating them. Once close, they grew distant with time. As the younger sister enters high school, their relationship once again begins to change. This time in an unusual direction.