Ishikawa, Ken

Nagai, Yasutaka

The Gokuhi-gumi are a band of space Yakuza. Led by "Genji of the North Star," they seek to go to war with other yakuza factions and generally cause trouble throughout the galaxy.

5001-nen Yakuza Wars

5001年ヤクザウォーズ

Yuuki, Masami

In the near future, large mecha called Labors are made to assist in various reconstruction projects in major countries around the world that are being threatened by global warming. In Japan, the government has enacted Project Babylon in order to conduct land reclamation. Labors are also being pressed into police and military service aside from civilian use.

However, terrorists are now attempting to use labors to make themselves heard, as well as common criminals, thugs and guerrillas. The National Police Agency established the Special Vehicles Division, an all-labor task force to combat the potential use of labors for criminal/terrorist activities.

(Source: MU)

Kidou Keisatsu Patlabor

Mobile Police Patlabor

機動警察パトレイバー

Adachi, Mitsuru

The story is set in a place very similar in appearance to Earth in the Edo period. However, Adachi (the mangaka) regularly reminds the reader all throughout the series that the setting is another planet in the distant future which just happens to look like Earth.

After the death of his mother, Shichimi sets out to join his step-brothers and -sister who live together in Karakuri Tenement, a place provided by the father they have never met. He finds out that each of them had different mothers (all of whom have died), but were fathered by the same man. Not long after Shichimi's arrival, the siblings decide to journey to visit the graves of each of their mothers. On this journey, they encounter many dangers.

(Source: Wikipedia)

Nijiiro Tougarashi

虹色とうがらし

Manabe, Jouji

It`s face-to-face confrontation when Kahm stares down her father and refuses to end her relationship with Tetsuya. In retaliation, her father sends a punitive fleet to Earth -- with orders not only to crush the rebellion but to annihilate the entire solar system!

(Source: Amazon)

Outlanders

アウトランダーズ

Shirow, Masamune

The main plot revolves around the Yamata Empire's plan to destroy all the galaxy's negative karma  using a massive technological reactor called the Nāga Generator. Unfortunately, negative karma cannot simply be destroyed, it must be atoned for. However the leader of the powerful mystic Buddhist Fuze Clan plans to stop the destruction of the negative karma which will end up creating the nine-headed Nāga and destroy the world if not the whole universe. To help in stopping the creation of the Nāga, the clan summons a Shinto god known as Susano, the Warrior God of Destruction. The powerful, arrogant, and homicidal god faces challenges. These include the Empire and the clan leader's own daughter, the bratty sorceress Seska, who is possessed by the power of the negative Karma and a powerful magic formula.

(Source: Wikipedia)

Senjutsu Choukoukaku Orion

Orion

仙術超攻殻 ORION

Humor is the only defense against insanity in a world where the crime is so bad that the cops need armored tanks! Such is the world of Leona, ace tank-cop. In her pet tank Bonaparte, she'll either save the city of Newport... or destroy it trying! In No More Noise, Leona recruits some help to catch some slippery crooks—help that's rather crooked itself! The villainous and sexy Puma sisters become duly deputized officers of the law in this latest chapter of Dominion!

(Source: Dark Horse)

Dominion C1 Conflict

Dominion Conflict One: No More Noise

ドミニオンC1コンフリクト

Set in the fictional city of Newport, Japan, in a future in which bacterial air pollution has become so severe that people must wear gas masks when outdoors, the series follows a police squadron that uses tanks.

(Source: Wikipedia)

Dominion

DOMINION

An bonus chapter included with the final volume of Getter Robo Āḥ. Dr. Hell discovers a biomechanical lifeform known as "Kedora" in the depths of Bardos Island, and realises that he can use it to fight Mazinger Z. 

The story of this chapter was loosely adapted into the sixteenth episode of Shin Mazinger Shougeki! Z-Hen.

Mazinger Z : Relic of Terror

Nagai, Go

One of the first Super Robot manga and the one that introduced most of the traits of the Mecha genre. Constructed with the Super-Alloy Z, Mazinger was built by Professor Juzo Kabuto as a weapon against the Mechanical Beasts of the evil Dr. Hell. Koji Kabuto, the grandson of Professor Kabuto, becomes the pilot of Mazinger Z when his grandfather is killed, and battles from there on against Dr. Hell and his allies. This is the first series that introduced the concept of a pilot inside a Mecha, which all series from then on have followed.

(Source: MU)

Mazinger Z

マジンガーZ

Ishinomori, Shoutarou

An evil secret society called the Black Cross Army threatens world peace, and only an elite task force known as the Earth Guard League (EAGLE) can stop them. After the Black Cross Army destroys EAGLE's headquarters across Japan, only five young recruits survive. Hiding in a secret underground base, they are given enhanced battlesuits that empower them with superhuman abilities, transforming the youths into an unstoppable squad to combat evil.

(Source: Seven Seas Entertainment)

Himitsu Sentai Gorenger

Super Sentai: Himitsu Sentai Gorenger

秘密戦隊ゴレンジャー

While pursuing a criminal, the pretty but reckless interplanetary police officer Birdy Cephon Altirra accidentally kills Tsutomu, an earthling high school student. To make amends, Birdy is forced to share her own body with Tsutomu's spirit so that he can continue his own life. At first, Tsutomu knows nothing about his situation but soon discovers that his body is starting to take certain actions without his mind ordering it. In times of action, Birdy takes full control of their shared body, transforming it back into her original female form.

(Source: MU)

Tetsuwan Birdy

Birdy the Mighty

鉄腕バーディー

Obata, Takeshi

His name is Tokijirou Kaizou, a brilliant scientist who has decided to spend his waning years taking things much easier: caring for his family, farming on his own plot of land...and transforming himself into a 2000-horsepower cyborg!?

(Source: OneManga)

Included one-shots:
Volume 3: Cyborg Jiichan Gaiden (pilot)
Volume 4: Long Shoot

12 Manga Like Transistor Venus