Overpowered and Really Cool MCs

Isekai (in world) Apocalyptic ~

‘This is a development that I know of.’ The moment he thought that, the world had been destroyed, and a new universe had unfolded. The new life of an ordinary reader begins within the world of the novel, a novel that he alone had finished.

Time travel (From future to past)

"Now that I'm back, I won't allow my loved ones to die again!"
The Shadow Labyrinth - the most catastrophic existence humanity has faced in history.
Desir Arman is one of the six remaining survivors of mankind within it.
The six attempt to clear the final level of the labyrinth but ultimately fail, and the world comes to an end.
However - when Desir thought he would meet his demise, what is revealed before him is the world...

Power rebirth/boost~

10 years ago, the monster horde from the rift formed from space and time started attacking the mankind. At the same time, people have started to awaken the power and began hunting the monsters for fame and money Lee SungHoon, in need of money because of his mother’s sickness, takes a dangerous job to help hunt those monsters four times a month by acting as a bait for the hunters But one day, he is heavily injured by a monster and remembers his past life as a sorcerer

Power rebirth/boost~

After the revivification and return of the spirit energy, men and women did their best to capture every strands of spirit energy and train, except Lu Shu, with his Negative Emotion System, he becomes stronger by taunting others! He only wanted to protect his younger sister, but the change of an era in unavoidable, then all he could do was... to taunt others in passing, and become the strongest! Then, are you ready? Here comes Lu Shu, 'The Great Demon King'

Reincarnation ~ Time travel (past to future)

Jung-woo, who was reincarnated in the past and tried to conquer Murim, continued his conquest.
Because of Shin-Ryong, who is left in a reincarnation cycle along with him, he fails to conquer Murim.
In the end, even the fifth attempt fails and he is reincarnated into modern times. Reincarnating into the
modern world changes Jung-woo's passion and dream. He seeks a battle with a powerful enemy, but he's too
powerful for most.

Reincarnation ~

The worst student of Westrod Academy, the disgrace of the Blake House.
A new soul enters the lifeless body of Frey Blake, the boy who couldn’t handle his painful life and chose death instead.
“What’s with this body?
I’ll have to check every little detail of it.”
The Great Mage Lucas Traumen.
He earned his chance at revenge by gaining the flesh and bones of Frey Blake the disgrace!
And now begins the interesting adventure of the Great Mage who return

Rags to riches ~ Hidden Power ~

This is a world whose peace was destroyed by the Shadow Lord, ‘Secneum’. ‘Niro’ is a half-elf, half-human boy who lost his parents as a baby and was adopted by a slave couple. In this world, slaves are not treated as humans. Since Niro’s adoptive parents are slaves, they are mistreated and eventually lose their lives. Now Niro is alone once more, and must shoulder the burdens of his family and protect his siblings

In world isekai ~

26-year-old Jung Si-woo never had any friends, because there was nothing interesting about him. He lived an average life as an average person in an average world. But suddenly, the earth faced a great change when Mysterious floating 'Sky Castles' appeared. The 'Sky Castles' granted some people wings and powers, but unfortunately, Si-woo wasn't one of them.