Can you recommend which novels have the system as the main character?

Keeley, a simple plain Jane, hits the jackpot. [No, she did not win the lottery!] At least that's what she thinks when she marries the most eligible bachelor in New York City: Aaron, a wealthy cold-hearted heartthrob and Tycoon. She wants to show the world that she deserves her position and bends over backward to fit into his world. One beautiful day, Aaron hands her a document asking her to sign. A divorce paper... "She's pregnant, and I need to take responsibility." That is the last thing that keeps on playing in her mind before she takes her last breath. Keeley dies, a 'hit and run'. [End of story. Not!] For some unexplainable reason, she wakes up as her younger self. A young high school girl, around the time when she first meets her cheating husband. Remembering her life with Aaron before she died, she makes a promise to herself that she will do everything in her power to avoid him at all costs. Will she be able to keep her promise when Aaron has his own plans as well, specifically for her? Or will she repeat history and fall for him once more... Why not journey with me and find out the truth behind their story. *Cover art by polkadottedscrunchie*

Ray, a super nerd virgin otaku student was transmigrated into a game based on galge. "Ding, please prevent the main heroines from falling in love with the protagonist Rewards: Elementary Cooking skills. Penalty: The host will lose his house and all his property." Wait, WHAT THE HECK!!! I don't want all of this, please return me to my old world!! "Ding, It was indicated that the host wants to reject the mission. Reject the mission and immediately gain the penalty Y/N" NOOOOOOOO, What in the seven hell has I did to ever deserve this thing!!! Follow the journey of Ray and the absurdity of the system in this story. Other tags: Beast taming, School life, R-18, MILF, Weak to strong, Yandere, Evolution, Annoying system, Super annoying system, Super super annoying system don't complain you have been warned. I don't own the cover. Hi everyone, I have created a poll in chapter 40, please feel free to join if you have any ideas or Spirit beast you wanna see in this story ^_^. I know I can't make everyone happy, but I'll try my best, and thank you to everyone who has supported this story. Discord: https://discord.gg/henXAtbX

Synopsis Kuramoto Daisuke, a freshman in High School was suddenly exposed to someone vanishing in front of him. Turns out he was admitted to a Special Class full of Isekai Heroes that were regularly summoned to Otherworlds since the start of their Middle School. He was told that he was to become their Support to prevent each of the Heroes' fate of dying in the world they were summoned into. Though mediocre, he realized that his ability has a great potential but it needs a lot of hard work on his part. Unconvinced of being just the Support Character, he vowed to excavate his mediocre ability, all the while supporting the Heroes using it. And maybe more. Join my Discord Server: https://discord.gg/BWBWUrU

Bell Cranel was rejected by every familia he tried to join until he met Hestia. In a few, he was rejected quite violently. And in one particular instance, he was thrown out and bashed his head against a wall. Well, that's apparently where I come in. Not sure how and why I'm here. Not even sure who 'I' really am at this point since Bell's memories are definitely clearer than 'mine'... But I guess we're doing this. Hopefully I've got some useful cheats. Maybe?

He Chuan transmigrated to an alternate world where everyone could reincarnate. In this world, all citizens who reached 18 years old could acquire a chance to temporarily reincarnate to another world. They could reincarnate to various worlds such as an Eastern fantasy world, Xianxia world, Western fantasy world, an urban world with advanced martial arts, or even a sci-fi world of the future. They would acquire a mission along with the ability required to survive in that particular world. If they successfully completed the mission, they would become a permanent Reincarnator. They could then embark on the journey of being rich and successful. If they failed the mission, they would become ordinary commoners. The gates to the new worlds would be forever closed to them. He Chuan reincarnated to his first world. [You reincarnated into a world of martial arts. You are an orphan and a loser. You awakened the Deduction System.] He Chuan devoted himself to deducting various kinds of martial arts. He extracted the essence of each technique and merged them into a unique system. In the end, he became the greatest legend in Jianghu. [You acquired S rank evaluation. You may choose to keep the power you gained during this reincarnation and use it again in your future reincarnations.] He Chuan chose to keep the Deduction System decisively. He then reincarnated to his second world. [You reincarnated to a fantasy world. You are talented and are the eldest son in the royal family.] Sit back and enjoy as He Chuan breaks through the limits of the world and crushes the void.

Dying and meeting a being who made him his new brother and promised to reincarnate him into the body of the strongest person of that world, what could go wrong with this right?....Well let's see how our protagonist deals with this when he finds himself inside a body that is destined to be strongest, which he will achieve no matter what. P.S.: It's not a serious story just a light read like a casual fanific about a guy reincarnating into Black Clover with some wishes.