One Piece: Capitalist Brook's Crew Expansion Plan - Chapter 12: - : Sparring

Shao Qing’s only regret in life is that she blindly fell in love with a worthless man. She gave up everything for him, but in exchange was run over by his conniving mistress when she was close to her delivery date. Fortunately, Heaven left her a way. Crimson rain fell from the sky, the end of the world arrived, she resurrected in the morgue and gave birth to a little monster. Turning into a half human, half zombie freak; her son neither human, nor monster; they have no other choice but to rely on zombies’ crystal nuclei to develop their special abilities and continue living. This debt, she’ll definitely repay that cheating couple!

- Description from Novelupdates

mc gets transmigrated to Fallout New Vegas with the merchant system. let the questionable adventure begin.

In the era of universal mechas, people can go to the endless abyss, collect materials, strengthen and forge their own mechas, and master the power of destroying the world.

Jiang Chen traveled through time and awakened his talent [Immortal Unarmed]. Once the mecha is broken, he can permanently absorb its power and receive multiple bonuses.

…

At the bottom of the abyss, when the Old Demon God finally broke the Titan mecha with great effort, a hand stretched out from the fragments and held down its head.

“Congratulations, you have unlocked my limiter.”

- Description from novelbuddy