UFO Robo Grendizer

Duke Fleed is a survivor of the Fleed Planet who is escaped to the Earth, onboard a mysterious "spaceship", where is raised by Dr. Umon as his adoptive son, and known as Daisuke Umon. Years after his arrival, he's faced with the threat of King Vega and his army, who want to conquer the Earth. With his friends Koji and Hikaru (and later his younger sister Maria Grace), Duke decides to fight back using his best weapon - the almighty Grendizer.

Future Robot Daltanious

It is the year 1995. Earth has been conquered by an alien army from the Saar cluster known as the Akron. The cities of Earth have been destroyed, and the remaining survivors live in harsh shanty towns and villages. Kento, a war orphan, hides within a cave along with his companions in order to escape some bandits. In the cave, they find the secret base of Dr. Earl, who was an inhabitant of the planet Helios, a planet conquered by the Akron. Dr. Earl then fled to Earth, bringing with him the greatest achievement in Helian technology: the super robot Daltanius, whose power is increased when combined with the intelligent lion robot, Beralios. Dr. Earl entrusts the fight for Earth to Kenta, who happens to be a descendant from the long disappeared Helian royal line. (Source Wikipedia.org)

The King of Braves: GaoGaiGar

In the year 2005, a race of alien monsters called Zonders emerge from underground and launch a series of attacks on the city of Tokyo. The only defense against these creatures is the secret agency known as the Gutsy Geoid Guard (or 3G) and their ultimate weapon, the awesome giant robot GaoGaiGar. GaoGaiGar's pilot, Guy Shishio, is a former astronaut who was nearly killed two years before when the Zonders first crashed to earth. Guy's life was spared when a mysterious robot lion called Galeon pulled him from the burning shuttle and brought him to Earth. Guy's father, Leo, then used Galeon's technology to rebuild his shattered son as a cyborg, in the hopes that he could stop the aliens when they appear. Now, with Galeon as its core, GaoGaiGar fights to protect Earth. He is aided by a team of transforming robots and by a young boy named Mamoru, who has the power to purify the Zonders' cores, and seems to be connected to the mysterious Galeon. (Source: Anime News Network)

Muteki Koujin Daitarn 3

Souzou Haran was a brilliant scientist that was conducting research on Mars. He created a form of cyborg life with the ability to think for itself. These cyborgs, dubbed the Meganoids, soon ran out of control and killed Dr. Haran along with his whole family, save his youngest son, the 16-year-old Banjou Haran. Banjou escapes from Mars on a rocket with a solar-powered super robot called Daitarn 3, which was built with the special metals of Mars. Now eighteen years old and living on Earth in a luxurious mansion, Banjou fights against the Meganoids with the aid of his faithful butler Garrison and his two gorgeous companions Reika and Beauty. Together they must stop the evil Meganoids which aspire to turn all humans into cyborgs and thus "improve" the human race. (Source: AniDB)

Mazinger Z

From the island of Bardos in the Aegean Sea comes a new threat to humanity in the form of Doctor Hell and his army of mechanical beasts. However, a new hero stands in his way: Mazinger Z, a giant robot built out of the indestructible metal chogokin and equipped with an arsenal of advanced weaponry. Piloting Mazinger Z is hotheaded teenager Kouji Kabuto, who strives to avenge the death of his grandfather and protect Japan from Doctor Hell's forces. (Source: Anime News Network)

Great Mazinger

A manga comic book and anime television series by manga artist Go Nagai, made as a direct continuation of the successful Mazinger Z series. It was aired on Japan in 1974, immediately following the end of the first Mazinger series.

Getter Robo: Armageddon

Sent to jail after being accused of murdering Getter Robo creator Dr. Saotome, Ryoma Nagare must once again team up with his former comrades and pilot Getter Robo when Saotome returns from the dead and threatens humanity by unleashing his greatest creation - the Shin Dragon. Their efforts, however, are in vain as they fail to stop a nuclear warhead from hitting Shin Dragon, resulting in a massive Getter Ray contamination that wipes out 99% of the planet's population. Thirteen years after this great catastrophe, mankind continues to fight for survival against the Invaders. Out of the remains of the nuclear blast comes Shin Getter, piloted by the artificial human Go. With remnants of the Japanese military by his side, Go - along with co-pilots Kei and Gai - must use Shin Getter to exterminate the Invaders once and for all. (Source: Anime News Network)