Space Knight Tekkaman

Tekkaman is just an average bright boy in his everyday life. However, modern science can turn him into a mighty space warrior. This becomes a reality when aggressive aliens come from space to invade our planet. Armed with a space lance, Tekkaman gallantly goes into action against the grotesque space creatures. During his battles he encounters a mysterious young man from another planet who helps him out whenever he is in danger. (Source: Absoluteanime)

The Guyver: Bio-Booster Armor

Shou and his friend, Tetsurou, stumble upon a strange orb-like mechanism, the Guyver Unit, in the woods. It physically bonds with Shou and turns him into the alien soldier, Guyver. His mission is to protect the Guyver Unit from the Japanese corporation known as Chronos. They are after it and two other units just like it. To retrieve the object, they send out vicious monsters known as Zoanoids. So no one is safe in Shou's life; not even himself.

Gunbuster

In the very near future, a race of huge, insect like aliens is discovered traveling the galaxy. These aliens seem dedicated to the eradication of the human species as it takes its first steps away from the solar system, and they are getting closer and closer to Earth. Humanity has responded by developing spacegoing battleships and giant fighting robots. These robots are piloted by the best and brightest of Earth's youth, picked from training schools around the world. The story begins in the year 2023, not long after the first battles with the aliens, and centers on young Noriko Takaya. Although Noriko's father was a famous Captain in the space fleet who was killed during one of the first battles of the war, her own talents as a pilot are questionable. Nonetheless, she has entered a training school. Through the series Noriko, joined by the beautiful and talented Kazumi Amano, will fight to overcome the trauma of war, the doubts of her peers, and her own lack of confidence. (Source: AniDB)