If you're looking for manga similar to Godzilla vs. Space Godzilla, you might like these titles.
This incarnation of Ultraman, now called "Tiga," finds the 100-foot tall hero revived in the year 2049 and facing a world ill-equipped to handle the onslaught of gigantic beasts that are peppering the globe. Relying on his martial-arts prowess and his three modes of combat - Sky (flight and speed), Power (strength), and Omni (a balance of the two) - Tiga goes toe to toe with the most terrifying collection of monstrous giants and alien invaders ever to plague the planet.
Universal Century 0079. The original Duchy of Zeon end of the war a year dominated army, was starting to show color in the color of the border on the success of the federal military mobile suit development. In addition, the forced conscription of boys to girls in order to ensure personnel guileless yet lost the war.
The story takes place in U.C. 0084 in the form of a video documentary. It is based on interviews with soldiers and officers of the Earth Federation and the Principality of Zeon who participated in the final battle of A Baoa Qu during the end of the One Year War in U.C. 0079
Beginning four years after the one year war, 0083 starts with the arrival of two new Gundam units to be used for gravity testing. Things take a turn for the worse when members of Zeon steal Unit 2 and the nuclear warhead it that it has been armed with. Young test pilot-in-training Kou Uraki, piloting Gundam Unit 1, must now capture the stolen Gundam before it can be used to fulfill Zeon's mysterious "Operation Stardust".