April 10th. Yesterday was the last day of spring vacation, so starting this morning it was a school day. After being woken up by his cute little sister, Itsuka Shidou believed that it would be the start of another normal day. As for predicting the chance meeting with the girl who called herself a spirit...... Along with a sudden shockwave, the townscape vanished without a trace. In a corner of the street which had now become a crater, the girl was there. "�”You, have you come to kill me too?" She is the disaster that will destroy humanity, a monster of unknown origin, and a being rejected by the world. There are only two ways to stop this girl: annihilation, and conversation. His little sister Kotori, wrapped in a military uniform, thus said to Shidou: "Since it's like this, just go date her, and make the spirit fall for you!" "Wh.. whaaaaaaaat!?" Enter a new age of boy meets girl!!

From Horobi no Michi:

Clockworkers- mechanical men, created during the war as a weapon to kill as many as possible. That war may be long over, but rogue Clockworkers are still roaming about, spreading fear and death wherever they go.

Machina's a member of the CWA, an organization dedicated to the destruction of these rogue robots.

Along with Deus, her Clockworker partner, she travels the country in pursuit of these dangerous robots...

The hero is Dr. Kishiwada, a brilliant but demented scientist, who creates bizarre mechas, battles the forces of evil, or just mucks about. There are many parodies of B-grade sci-fi movies and of TV. Crazy, slick, and very funny.

From Mobots:

Renton is a 14-year-old boy who occasionally helps out his grandfather as a mechanic. But his feelings of dissatisfaction and frustration grow as his mundane and routine work cloud his visions for his future, and he dreams of flying around the world. It isn't until one day, a large human-like mech, a LFO (Light Finding Operation), falls from the sky in front of Renton, and appearing from the depths of the machine is a beautiful young girl named Eureka. And as she asks the dumbfounded Renton for repairs, the two will embark upon a fantastic journey into the unknown.

In Esora, a city built around a colossal radio tower, a young man -- Nishina Kazu -- tires of the unchanging everyday world that he captures on his video camera. One day, as he is video taping some abandoned buildings, there is suddenly an explosion and a girl called Mamiru Ai appears before him. This marks the beginning of the change from the ordinary that he had been hoping for...

In this world there are mysterious machines known as TREMORS. The reason they came and who built them are still unknown.The most mysterious part of the tremors, however, would be their ability to continuously EVOLVE. And in this world a boy is on a journey looking for his missing father.

From TokyoPop:

After having finished a job at Research Colony Mendel, a mysterious mobile suit approaches the colony--likely with hostile intent. When Lowe Gear intercepts in the Red Frame, the pilot opens fire... and thus begins another exciting adventure set in the popular Gundam Seed universe! Mobile Suit Gundam SEED X Astray continues where Gundam Seed Astray R left off!

Great Mazinger starts after the defeat of Mazinger Z. Tetsuya Tsurugi is the new protagonist, piloting the powerful Great Mazinger, a creation of the once thought dead Kenzo Kabuto, the father of Koji Kabuto. This time the enemy is the Mycene Empire and its powerful robots.

All humans in this world can use the power of the light of mana, and those who can't are considered to be subhuman 'Norma.' The world is like a peaceful utopia, and the celebrated princess Angelize leads a happy life. She believes that the only darkness left in the world is the existence of the horrible Norma. However, in a ceremony on her 16th birthday, the truth is revealed--Princess Angelize is a Norma. Now she is going to learn what her society does to Norma. She is sent to an isolated island full of others like her, who are taught that the only reason they are allowed to live is in order to fight to protect the peace of this world. Now "Ange" is part of a squad that pilots Paramails and fights invading extradimensional dragons.

Mazinger Angels chronicles the adventures of four women who pilot giant robots in the Mazinger vein. The concept is a spoof on the late 70's and early 80's popular TV series Charlie's Angels.

Three of the robots, Aphrodite A, Diana A and Minerva X are from the original Mazinger Z series, while Venus A is from the Great Mazinger series. Their pilots are also traditional characters from Go Nagai's universe, Sayaka Yumi and Jun Hono from Mazinger Z and Great Mazinger respectively, and Hikaru Makiba and Maria Fleed from Grendizer.

The style of the manga highlights the sex appeal of both the characters and the mechas, sometimes similarly to the way Aika's female characters are shown. (taken from wikipedia)

From CPM:

An alien armada from Jupiter has amassed enough power to destroy all of Earth's defences. Earth's final hope lies in the Space Battleship Nadesico, a ship created using recently discovered extraterrestrial technology.
Can the Nadesico's rag-tag crew overcome their idiosyncrasies and defeat the alien fleet, or will Earth's last hope be lost?

The manga differs greatly from the anime

It is a parody of the first Mega Man game done in Ishikawa's style.

Artist's Twitter: https://twitter.com/wv92OsY8GKSFlJU

Heero attempts to live a normal life after the war. But his "peaceful" life is disturbed when someone manages to steal Wing ZERO. He rushes to search for it, and is then faced with an unlikely foe. On all accounts, Ground Zero can be considered a doujinshi due to its lack of consistency and subjected humor. However, it tackles deeply into the characters' morale and philosophies regarding war, peace, and of course, the gundams. Like Battlefield of Pacifists and Blind Target, Ground Zero are *possible* events that take place in between the TV series and the OVA, Endless Waltz.

A re-imagining of Gurren Lagann. In this alternate version of TTGL, Simon lives in Tepelen city and dreams of becoming a Gunmen pilot after having seen the stars through a crack in the sky. One day, he comes across a strange small Gunmen. The hatch opens, and out comes a beautiful girl named Nia.

The official Infinite Stratos Anthology comics.

One night in the Windbloom Kingdom, Princess Mashiro Blan de Windbloom is assassinated in her sleep. Some days later, the main character, an anonymous boy, arrives in Wind City, capital of Windbloom. Using a gem passed down from his mother, he takes up the identity of Mashiro and joins Garderobe. The story follows his experiences in Garderobe and later his battles against those who would seek to destabilise the peace.

In the Mazinger Otome series:

V.1 - Mazinger Otome

V.2 - Mazinger Otome Taisen

The genius robotics professor, Dr. Komyoji has created Jiro (who has the ability to transform into Kikaider) – a humanoid robot tasked with the protection of Dr. Komyoji’s son, Masaru, and daughter, Mitsuko. Gifted with a conscience circuit, which has the power to simulate real emotions that helps to distinguish between “right and wrong”, Jiro must protect Mitsuko and Masaru from the evil Dr. Gil who wants Jiro to join his army and aid in his goal of world domination.

From Dark Horse:
Dark Horse proudly presents another of the crown jewels of international graphic fiction—Astro Boy! Created by the late Osamu Tezuka, a revered animator and cartoonist—who created over 150,000 pages of comics in his career!—and considered the Walt Disney of Japan, his Astro Boy was the first manga series to be adapted to animation and became a worldwide phenomenon, making Astro Boy the Mickey Mouse of anime—a jet-powered, super-strong, evil-robot-bashing, alien-invasion-smashing Mickey Mouse, that is!
Exciting, whimsical, and touching, Astro Boy hearkens back to the classic era of comics and animation, featuring stories that readers young and old will enjoy.

The Zaku, "The Father of all Mobile Suits", a title bestowed on to this mobile suit long after its creation & deployment to the battlefield; but this is not the story of the Zaku's exploits during the Zeon War of Independence, later called the One Year War. Neither is it the story of a new type of piloted, independently powered mobile machine. A machine that would be powered by a state of the art thermonuclear reactor, but due to the secrecy and inherent danger involved in developing a project of this kind, its development was outsourced to Hosioka, a small steelworks industrial plant and its employees, this is their story.