One Piece: The Soul Purchasing Pirate - Chapter 29

Shen Zhixian transmigrated into a book as a cannon fodder master who hatefully severed his disciple’s spirit root. This disciple fell into the devil’s path and returned to make mincemeat out of him.

Shen Zhixian just happened to transmigrate into the last moment of the master’s captivity, and then he was reborn again.

After rebirth, he devoted himself to fostering and supporting his disciple, only to discover later that his disciple was also reborn.

Even worse, the disciple still retained the memory of his life before rebirth.

Shen Zhixian: …Disturbed.

Afterward, he realized one truth: Being a master is a high-risk occupation. Not trivial at all!

- Description from Novelupdates

When crossing over to multiple books, Ren Shuhan found that every protagonist Shou was waiting for him to start chasing them in the crematorium.

“Don’t waste your time waiting,” He advised sincerely, “There are more 0s than 1s, so I’m not going to chase someone that is not interested.”

The protagonist Shou (sneering): Oh, there will be a day where you’ll lick the ground I walk on.

After waiting and waiting…

Ren Shuhan: “This is the wedding invitation for my childhood friend and I’s wedding.”

On the wedding night, Ren Shuhan removed the veil: “Baby, I’ve come to marry you.”

“Don’t you know that life is nothing but a play where you are the male lead and I am just a supporting character?”

“I know, but I don’t care.”

He was smiling, but Jiang Qingyue wept.

- Description from Novelupdates

Zheng Tan somehow returns to the year 2003, turning into a black cat. Picked up from a rubbish heap by the Jiao family, he is given the name “Charcoal”, and so begins the life inside Professor Jiao’s family. Zheng Tan remembers that he was once a person, but currently his body is that of a cat. He has no way of speaking the human language, but can understand it, and even retains the thinking and IQ of a young 20 year old youth. Read along as he adapts to this new world, and somehow tumbles from a group brawl to catching a thief.

- Description from Novelupdates