Multiple isekai’d characters

Yoonsoo is the successful author of a popular fantasy series. Just as she’s about to start work on a new series, Imperial Prince Einzen Kyte, the worst villain she created has kidnapped her into the world of her own story.
• Spoiler? – not really
• Who? – MC and secondary character*
• Important? – slightly

Mary Albert remembers that this world was an otoge she played in her previous life, and she turns out to be a villainess who meets ruin. The obvious reaction is to carefully avoid the destruction ending, right?
• Spoiler? – not really; established once they show up
• Who? – MC and secondary characters
• Important? – to secondary characters’ arc

Ripley decides to make the best of her reincarnation as an extra in a novel, but it ends up going south. She can remember up to drinking alone at a party but she wakes up in the male lead’s bed.
• Spoiler? – ehhhh
• Who? – MC and side character
• Important? – briefly mentioned and a short interaction but also extremely important to character development
• TW – sex w/ one party drunk; kidnapping; attempted murder; attempted rape

Crown Prince Cecil was so brilliant that everything in life was easy to the point of boring him. Until one day, his fiancée Bertia suddenly says, “Prince Cecil, I am a villainess!”
• Spoiler? – pretty obvious
• Who? – love interest and antagonist
• Important? – yes

I reincarnated into a novel inside the body of a villainess. From the moment I realized this, I’ve had only one goal: escape this world.
• Spoiler? – not really
• Who? – MC and side characters
• Important? – no, aside from some important lore and minor plot points
• TW – attempted suicide; attempted rape; child abuse; sorta incest (one-sided)

I became the secretary of a tyrant in place of my clumsy brother to survive.
But I have so much potential for it. I’m so darn good at my job. Because I served the tyrant so well, everyone must have a happy ending.
Well then, shall I quit being a secretary and live a leisurely life now?
“Do you want to die?”
• Spoiler? – yes but revealed fairly early
• Who? – MC and antagonist
• Important? – yes
• TW – drugging; attempted

Valerie thought she’d be a geniu in this world by using her knowledge from her past life. But when her magic can’t get past basic and her teacher shares a prophecy of a tiger coming to attack, she opts out. Everything’s fine until she gets engaged to Duke Dwello.
• Who? – MC and main supporting character (isekai’d in different ways)
• Important? – yes
• TW – child abuse; PTSD

Was I reborn? In my previous life, I was a designer who had just graduated, but I then died in an accident. Adelaide, that’s my new name. My new life feels very boring, but then I heard news that there is a girl who can move between dimensions. I decided to go to the capital to meet her; is there something waiting for me there?
• Spoiler? – no
• Who? – MC and antagonist (isekai’d in different ways)
• Important? – yes

In order to clear the name of 'Emi,' a girl who had reincarnated as Remilia, the villainess of an otome game, the real Remilia who had been watching all along inside, awakens.
• Spoiler? – obvious
• Who? – antagonist and side character
• Important? – yes

She has been reborn into the world of an otome game as the villainess, Irene. Using her memories of her former life, she recognizes flags indicating she’s en-route to the bad end, so she makes a plan to conquer the last boss—the evil King Claude—make him her lover, and see if she can open up a new route.
• Spoiler? – obvious
• Who? – MC and antagonist
• Important? – yes
• TW – attempted rape