Primus (Transformers) is the creator-god of all Cybertronian life.
Unicron (Transformers) is considered to be the Cybertronian god of destruction whereas his brother, Primus, represents creation.
The Consortium (Generator Rex) in their new forms after being infused with the power of the Meta-Nanites.
After being infused with the power of the Mantra Reactor, Asura (Asura's Wrath) gained the power of Pride, Lust, Greed, Sloth, Vanity, Violence, Melancholy, and Wrath, allowing him transform into his most powerful form, Asura The Destructor.
After exposure to the Celestial Ship, Apocalypse's (Marvel) body became altered with mechanical modifications making him into an all powerful cyborg mutant.
After traveling the universe, AMAZO (DC/JLU) transcended his own nanotechnology, becoming a nigh-omnipotent machine capable of overwhelming the Justice League.
Brainiac (DC) is a highly intelligent being capable of transferring his consciousness into powerful robotic/cyborg bodies that are able to do great damage to Superman.
In the Batman Beyond timeline, Brainiac (DC) was able to assimilate the entire Earth.
When Lex luthor fused with Brainiac (DC/JLU) along with the Dark Heart, they were able to become one ultimate being with enough power to destroy the entire universe and rebuild it.
The Anti-Monitor (DC) is one of the most formidable and powerful beings in the known universe.
Master Albert (Mega Man ZX Advent) after fusing with Model W to become the "Ultimate Mega Man".
Omega (Mega Man Zero 3) also known "the Devil Reploid" and "the Ultimate Reploid" is an incredibly dangerous and powerful Reploid created by Dr. Weil. With his control over the Dark Elf, he uses it to increase his power to the point where is able to control every Reploid on the planet and even overwhelm Zero.
The General (Eon Kid) is a robot that possesses nearly unlimited supernatural powers that allow him to do virtually anything, he can even prevent all cosmic radiation entering the planets atmosphere.
The Devil Gundam/Dark Gundam (Mobile Fighter G Gundam) is a viciously powerful Gundam. While originally built to aid mankind, the Gundam malfunctioned and became a twisted menace bent on using its abilities of self recovery, self replication, and self evolution to become a nearly unstoppable force with the power to devour an entire planet.
Matrix (Valkyrie Crusade) is the transcendent mother of all machines.
Ragnarok (Valkyrie Crusade) is a transcendent WMD machine able to defy and kill deities.
Tengen Toppa Gurren Lagann (Gurren Lagann) is the most powerful mecha in the universe, spanning 10 million light years across with the power to rip holes in dimensions.
Cyber-Akuma (Marvel Super Heroes vs Street Fighter) is a godlike techno-organic being thanks to a combination between Celestial technology provided by Apocalypse and the power of the Satsui no Hadou. The cybernetic enhancements provided him with incredible speed, strength, and Ki manipulation that are able to strike fear into both M. Bison and Apocalypse.
With the power of the Infinity Stones, Ultron and Sigma merged into Ultron Sigma (Marvel vs. Capcom: Infinite). Alongside possessing the abilities of its fusees, Ultron Sigma also possesses power of the Infinite Stones, able to warp reality to his liking.