Collection of 3 short stories, the first two are Please save my earth related, but they are standalones and spoiler free:
PSME-Things accidently left behind
PSME-BIRTH
Cibi-01 no YaYaYa! (Cibi, right, not Chibi)

Mirai no Utena appears to be the story of a perfectly normal boy, Matsuyuki Takeru. He deals with his mother's death and the knowledge that he has a half-sister he's never met; falls in love; and muddles his way through entrance exams. But there's also a mysterious child, Zen, who keeps appearing. As Takeru gets to know Zen better, he is drawn into a centuries-old rivalry between two families, and his real life becomes more and more like the RPGs he loves, until he is literally fighting for his life.
(Source: ANN)

Since the conclusion of the original series, Rin and Arisu are leading happy lives. Their son, Ren, is a very normal boy. But one day, a man and a woman as beautiful as an angel appear in front of him and tell him about a power! What is this power Ren suddenly has? The much anticipated sequel to "Please Save My Earth"!

In the year 20XX the vast city of New York is under constant terrorist attacks at public places. The police is clueless and the culprit is roaming the city free. The police’s only witness died, and her clones are useless, so they are left with no choice but to receive the help of Jojo Schmit of the EPIA section, a section dedicated to ESP related phenomena.

Alice Sakaguchi has recently moved to Tokyo from her country home in Hokkaido... and she absolutely hates it. The air is polluted, there are far fewer of her beloved plants in the city than she would prefer, she can't seem to make friends at her new high school, and her seven-year old neighbor, Rin, is constantly bullying her. One day, Alice takes Rin to the zoo, where, as usual, the animals crowd around Alice when she gets near, and it seems that she can feel their thoughts. At the zoo, she runs into two of her male classmates, who she thought she had seen having a rather... intimate... moment a few days before. They tell her that they have been having the same dreams since junior high, extremely vivid dreams in which they are scientists observing the earth from a base on the moon with five others. Alice is fascinated by this and wants to know more. When she has one of these dreams herself, however, and the three of them start searching for the other four scientists, one of which turns out to be Rin, Alice's world begins to change drastically, and perhaps not for the better.

Living in regret that his formula gave birth to the atomic bomb, Professor Einstein sends two boys whose eyes can see the future on a train that travels at the speed of light before embarking on his own final adventure: death. His hope is that they will find "HER" and tell her his wish, for it is only she who can grant it.

Fifty years later, it is 2005 and the place is Tokyo. At last, "SHE" (Ruika) has been found... but Ruika has an unusual circumstance. For her mother's sake, she's been living as her dead brother since childhood. Does Ruika truly have the power to grant wishes? If she grants her mother's wish by becoming a boy, then no one can lead us into the GLOBAL GARDEN... Now it's a race against time and against each other, because everyone has a dark past and an ulterior motive for possessing the girl who can grant Einstein's wish.

This 4 volume manga is about Haruko, who after her mothers' death, gains her moms familiar and her witches name. Unfortunatly Silk, the cat familiar, has been unable to teach Haruko any magic but dream communication. But beware, if anyone finds out her witch name she'll have to obey that person. Is this real or is it all in her mind? (Source: MegKF)