Where MC has reincarnated or transmigrated into the body of a villainess, usually from an Otome game or webcomic/novel, whose fate is to meet a terrible end.
Where MC lived the life of a villainess, before being sent back in time, usually after meeting a terrible fate where it's revealed she was manipulated/betrayed into being villainous in the first place, by the seemingly angelic character everyone loved.
She then sets out to change that fate - in the Otome ones, it's typically by unintentionally taking over the role of the protagonist and earning the interest of the Male Leads.